diff --git a/src/components/ElementFloatPreview.tsx b/src/components/ElementFloatPreview.tsx
index c092cc5..08d0c30 100644
--- a/src/components/ElementFloatPreview.tsx
+++ b/src/components/ElementFloatPreview.tsx
@@ -3,6 +3,12 @@ import { TemplateElement } from '../types';
 import { mmToPx } from '../utils';
 import { renderLabelToDataUrl } from '../labelRenderer';
 
+/** 离屏单元素渲染时预留描边空间，避免画布边缘裁切表格线 */
+function getFloatPreviewPaddingMm(element: TemplateElement): number {
+  if (element.type !== 'table') return 0;
+  return (element.tableBorderWidth ?? 0.2) / 2 + 0.1;
+}
+
 interface ElementFloatPreviewProps {
   element: TemplateElement;
   renderScale: number;
@@ -17,10 +23,11 @@ export async function renderElementFloatPreview(
   renderScale: number,
   variableDefaults?: Record<string, string> | null
 ): Promise<string> {
+  const padMm = getFloatPreviewPaddingMm(element);
   return renderLabelToDataUrl({
-    widthMm: element.width,
-    heightMm: element.height,
-    elements: [{ ...element, x: 0, y: 0 }],
+    widthMm: element.width + padMm * 2,
+    heightMm: element.height + padMm * 2,
+    elements: [{ ...element, x: padMm, y: padMm }],
     rowData: null,
     rowIndex: 0,
     showBorder: false,
diff --git a/src/components/LabelDesigner.tsx b/src/components/LabelDesigner.tsx
index c75a419..b2aa6ea 100644
--- a/src/components/LabelDesigner.tsx
+++ b/src/components/LabelDesigner.tsx
@@ -1,7 +1,7 @@
 import React, { useState, useRef, useEffect, useCallback, useMemo } from 'react';
 import { createPortal } from 'react-dom';
 import { LabelTemplate, TemplateElement } from '../types';
-import { mmToPx, MM_TO_PX, shouldRenderElement } from '../utils';
+import { mmToPx, MM_TO_PX, shouldRenderElement, centerElementOnLabel } from '../utils';
 import type { ElementClipboardActions } from '../hooks/useElementClipboard';
 import {
   createDefaultTableElement,
@@ -327,8 +327,7 @@ export const LabelDesigner: React.FC<LabelDesignerProps> = ({
         id,
         type: 'image',
         name: `图片 ${n}`,
-        x: 5,
-        y: 5,
+        ...centerElementOnLabel(template.width, template.height, 30, 30),
         width: 30,
         height: 30,
         content: src,
@@ -421,6 +420,14 @@ export const LabelDesigner: React.FC<LabelDesignerProps> = ({
         };
       }
 
+      const centered = centerElementOnLabel(
+        template.width,
+        template.height,
+        newElement.width,
+        newElement.height
+      );
+      newElement = { ...newElement, ...centered };
+
       onChange({
         ...template,
         elements: [...template.elements, newElement],
diff --git a/src/components/PropSidebar.tsx b/src/components/PropSidebar.tsx
index 7241666..8fba2ad 100644
--- a/src/components/PropSidebar.tsx
+++ b/src/components/PropSidebar.tsx
@@ -997,7 +997,9 @@ export const PropSidebar: React.FC<PropSidebarProps> = ({
 
   const renderPropertiesPanelBody = () => (
     <>
-      <div className="pb-3 border-b border-[#3a3a3a]">{renderPreviewReferenceBackgroundFields()}</div>
+      {!selectedElem && (
+        <div className="pb-3 border-b border-[#3a3a3a]">{renderPreviewReferenceBackgroundFields()}</div>
+      )}
       {/* Label Canvas Dimensions */}
       {!selectedElem && (
         <div className="space-y-4">
@@ -1684,13 +1686,15 @@ export const PropSidebar: React.FC<PropSidebarProps> = ({
                   value={selectedElem.width}
                   onCommit={(val) => {
                     const wVal = Math.max(2, Number(val) || 2);
-                    let updated = { ...selectedElem, width: wVal };
                     if (selectedElem.type === 'qrcode') {
-                      updated.height = wVal;
+                      handleElemChange({ ...selectedElem, width: wVal, height: wVal });
                     } else if (selectedElem.type === 'table') {
-                      updated = scaleTableElementSize(updated, wVal, updated.height);
+                      handleElemChange(
+                        scaleTableElementSize(selectedElem, wVal, selectedElem.height)
+                      );
+                    } else {
+                      handleElemChange({ ...selectedElem, width: wVal });
                     }
-                    handleElemChange(updated);
                   }}
                   className="ps-field font-mono"
                 />
diff --git a/src/components/TablePropertyFields.tsx b/src/components/TablePropertyFields.tsx
index 4e5c9d9..d5498e7 100644
--- a/src/components/TablePropertyFields.tsx
+++ b/src/components/TablePropertyFields.tsx
@@ -14,6 +14,8 @@ import {
   updateTableCells,
   updateTableColWidth,
   updateTableRowHeight,
+  equalizeTableColWidths,
+  equalizeTableRowHeights,
   getTableColWidths,
   getTableRowHeights,
   getCellRawContent,
@@ -90,7 +92,17 @@ export const TablePropertyFields: React.FC<TablePropertyFieldsProps> = ({
       </div>
 
       <div className="space-y-1.5">
-        <span className="text-[10px] font-semibold text-[#aaa]">行高 (mm)</span>
+        <div className="flex items-center justify-between gap-2">
+          <span className="text-[10px] font-semibold text-[#aaa]">行高 (mm)</span>
+          <button
+            type="button"
+            onClick={() => onChange(equalizeTableRowHeights(elem))}
+            className="text-[9px] text-[#31a8ff] hover:underline cursor-pointer shrink-0"
+            title="将各行高度恢复为相等"
+          >
+            等分行高
+          </button>
+        </div>
         <div className="grid grid-cols-3 gap-1.5">
           {rowHeights.map((h, i) => (
             <div key={`rh-${i}`}>
@@ -111,7 +123,17 @@ export const TablePropertyFields: React.FC<TablePropertyFieldsProps> = ({
       </div>
 
       <div className="space-y-1.5">
-        <span className="text-[10px] font-semibold text-[#aaa]">列宽 (mm)</span>
+        <div className="flex items-center justify-between gap-2">
+          <span className="text-[10px] font-semibold text-[#aaa]">列宽 (mm)</span>
+          <button
+            type="button"
+            onClick={() => onChange(equalizeTableColWidths(elem))}
+            className="text-[9px] text-[#31a8ff] hover:underline cursor-pointer shrink-0"
+            title="将各列宽度恢复为相等"
+          >
+            等分列宽
+          </button>
+        </div>
         <div className="grid grid-cols-3 gap-1.5">
           {colWidths.map((w, i) => (
             <div key={`cw-${i}`}>
@@ -287,7 +309,9 @@ export const TableCellContentFields: React.FC<TableCellContentFieldsProps> = ({
 export function scaleTableElementSize(
   elem: TemplateElement,
   newWidth: number,
-  newHeight: number
+  newHeight: number,
+  startWidth = elem.width,
+  startHeight = elem.height
 ): TemplateElement {
   if (elem.type !== 'table') {
     return { ...elem, width: newWidth, height: newHeight };
@@ -296,8 +320,8 @@ export function scaleTableElementSize(
     elem,
     newWidth,
     newHeight,
-    elem.width,
-    elem.height,
+    startWidth,
+    startHeight,
     getTableRowHeights(elem),
     getTableColWidths(elem)
   );
diff --git a/src/labelRenderer.ts b/src/labelRenderer.ts
index f2d0a31..430fd57 100644
--- a/src/labelRenderer.ts
+++ b/src/labelRenderer.ts
@@ -422,12 +422,17 @@ function drawTableGridLines(
   ctx.beginPath();
 
   const inset = borderW / 2;
-  ctx.rect(
-    alignStrokeCoord(left + inset),
-    alignStrokeCoord(top + inset),
-    Math.max(0, width - borderW),
-    Math.max(0, height - borderW)
-  );
+  const right = left + width;
+  const bottom = top + height;
+  // 外框：描边完全落在网格区域内，避免 clip / 画布边缘裁切右、下边
+  ctx.moveTo(alignStrokeCoord(left + inset), alignStrokeCoord(top + inset));
+  ctx.lineTo(alignStrokeCoord(right - inset), alignStrokeCoord(top + inset));
+  ctx.moveTo(alignStrokeCoord(right - inset), alignStrokeCoord(top + inset));
+  ctx.lineTo(alignStrokeCoord(right - inset), alignStrokeCoord(bottom - inset));
+  ctx.moveTo(alignStrokeCoord(right - inset), alignStrokeCoord(bottom - inset));
+  ctx.lineTo(alignStrokeCoord(left + inset), alignStrokeCoord(bottom - inset));
+  ctx.moveTo(alignStrokeCoord(left + inset), alignStrokeCoord(bottom - inset));
+  ctx.lineTo(alignStrokeCoord(left + inset), alignStrokeCoord(top + inset));
 
   for (let r = 1; r < rows; r++) {
     const y = alignStrokeCoord(rowBounds[r]);
@@ -532,8 +537,8 @@ async function drawTableElement(
     );
   }
 
-  drawTableGridLines(ctx, elem, ex, ey, scale);
   ctx.restore();
+  drawTableGridLines(ctx, elem, ex, ey, scale);
 }
 
 function drawImagePlaceholder(
diff --git a/src/tableUtils.ts b/src/tableUtils.ts
index d9df40c..e301f26 100644
--- a/src/tableUtils.ts
+++ b/src/tableUtils.ts
@@ -56,6 +56,36 @@ export function getTableColWidths(elem: TemplateElement): number[] {
   return Array.from({ length: cols }, () => even);
 }
 
+/** 调整末项（必要时向前）使轨道总和精确等于 targetTotal */
+function absorbTrackSumDiff(tracks: number[], targetTotal: number, min = 0.5): number[] {
+  const result = tracks.map((t) => round1(Math.max(min, t)));
+  let diff = round1(targetTotal - result.reduce((a, b) => a + b, 0));
+  for (let i = result.length - 1; i >= 0 && diff !== 0; i--) {
+    const adjusted = round1(Math.max(min, result[i] + diff));
+    const applied = round1(adjusted - result[i]);
+    result[i] = adjusted;
+    diff = round1(diff - applied);
+  }
+  return result;
+}
+
+/** 按比例缩放轨道，严格使总和等于 targetTotal（不放大目标总量） */
+function scaleTracksToExactTotal(tracks: number[], targetTotal: number, min = 0.5): number[] {
+  if (tracks.length === 0) return [];
+  const count = tracks.length;
+  const floor = count * min;
+  if (targetTotal <= floor + 0.01) {
+    return absorbTrackSumDiff(Array.from({ length: count }, () => min), targetTotal, min);
+  }
+  const current = tracks.reduce((a, b) => a + b, 0);
+  if (current <= 0) {
+    const even = round1(targetTotal / count);
+    return absorbTrackSumDiff(Array.from({ length: count }, () => even), targetTotal, min);
+  }
+  const scaled = tracks.map((t) => round1(Math.max(min, (t / current) * targetTotal)));
+  return absorbTrackSumDiff(scaled, targetTotal, min);
+}
+
 /** 将轨道尺寸总和调整为 targetTotal（保持相对比例，末项吸收取整误差） */
 function scaleTracksToTotal(tracks: number[], targetTotal: number, min = 0.5): number[] {
   if (tracks.length === 0) return [];
@@ -73,6 +103,48 @@ function scaleTracksToTotal(tracks: number[], targetTotal: number, min = 0.5): n
   return scaled;
 }
 
+/** 调整单条轨道尺寸，保持轨道总和不变；优先由 index 之后的轨道吸收差值 */
+function resizeTrackKeepingTotal(
+  tracks: number[],
+  index: number,
+  sizeMm: number,
+  min = 0.5
+): number[] {
+  if (index < 0 || index >= tracks.length) return tracks;
+  const total = round1(tracks.reduce((a, b) => a + b, 0));
+  if (tracks.length === 1) {
+    return [round1(Math.max(min, Math.min(total, sizeMm)))];
+  }
+
+  const beforeSum = round1(tracks.slice(0, index).reduce((a, b) => a + b, 0));
+  const afterCount = tracks.length - index - 1;
+  const beforeCount = index;
+
+  const maxForIndex =
+    afterCount > 0
+      ? round1(total - beforeSum - afterCount * min)
+      : round1(total - beforeCount * min);
+  const newSize = round1(Math.max(min, Math.min(maxForIndex, sizeMm)));
+  const result = [...tracks];
+  result[index] = newSize;
+
+  if (afterCount > 0) {
+    const afterRemaining = round1(total - beforeSum - newSize);
+    const scaledAfter = scaleTracksToExactTotal(tracks.slice(index + 1), afterRemaining, min);
+    for (let i = 0; i < scaledAfter.length; i++) {
+      result[index + 1 + i] = scaledAfter[i];
+    }
+  } else if (beforeCount > 0) {
+    const beforeRemaining = round1(total - newSize);
+    const scaledBefore = scaleTracksToExactTotal(tracks.slice(0, index), beforeRemaining, min);
+    for (let i = 0; i < scaledBefore.length; i++) {
+      result[i] = scaledBefore[i];
+    }
+  }
+
+  return absorbTrackSumDiff(result, total, min);
+}
+
 /** 将 inner 区域均分给 count 条轨道（末项吸收取整误差） */
 function distributeTracks(total: number, count: number, min = 0.5): number[] {
   if (count <= 0) return [];
@@ -132,8 +204,14 @@ export function scaleTableTracks(
   const scaleW = newInnerW / startInnerW;
   const scaleH = newInnerH / startInnerH;
 
-  const tableRowHeights = startRowHeights.map((h) => round1(Math.max(0.5, h * scaleH)));
-  const tableColWidths = startColWidths.map((w) => round1(Math.max(0.5, w * scaleW)));
+  const tableRowHeights = scaleTracksToExactTotal(
+    startRowHeights.map((h) => h * scaleH),
+    newInnerH
+  );
+  const tableColWidths = scaleTracksToExactTotal(
+    startColWidths.map((w) => w * scaleW),
+    newInnerW
+  );
 
   return {
     ...elem,
@@ -456,14 +534,27 @@ export function updateTableRowHeight(
   rowIndex: number,
   heightMm: number
 ): TemplateElement {
-  const rowHeights = [...getTableRowHeights(elem)];
-  if (rowIndex < 0 || rowIndex >= rowHeights.length) return elem;
-  rowHeights[rowIndex] = Math.max(0.5, round1(heightMm));
+  if (rowIndex < 0 || rowIndex >= getTableRows(elem)) return elem;
   const pad = resolvePaddingMm(elem);
+  const innerH = getTableInnerSizeMm(elem).height;
+  const rowHeights = scaleTracksToExactTotal(getTableRowHeights(elem), innerH);
+  const isLast = rowIndex === rowHeights.length - 1;
+
+  if (isLast) {
+    const nextHeights = [...rowHeights];
+    nextHeights[rowIndex] = round1(Math.max(0.5, heightMm));
+    const newInnerH = round1(nextHeights.reduce((a, b) => a + b, 0));
+    return {
+      ...elem,
+      tableRowHeights: nextHeights,
+      height: round1(newInnerH + pad.top + pad.bottom),
+    };
+  }
+
   return {
     ...elem,
-    tableRowHeights: rowHeights,
-    height: round1(rowHeights.reduce((a, b) => a + b, 0) + pad.top + pad.bottom),
+    tableRowHeights: resizeTrackKeepingTotal(rowHeights, rowIndex, heightMm),
+    height: elem.height,
   };
 }
 
@@ -472,14 +563,55 @@ export function updateTableColWidth(
   colIndex: number,
   widthMm: number
 ): TemplateElement {
-  const colWidths = [...getTableColWidths(elem)];
-  if (colIndex < 0 || colIndex >= colWidths.length) return elem;
-  colWidths[colIndex] = Math.max(0.5, round1(widthMm));
+  if (colIndex < 0 || colIndex >= getTableCols(elem)) return elem;
   const pad = resolvePaddingMm(elem);
+  const innerW = getTableInnerSizeMm(elem).width;
+  const colWidths = scaleTracksToExactTotal(getTableColWidths(elem), innerW);
+  const isLast = colIndex === colWidths.length - 1;
+
+  if (isLast) {
+    const nextWidths = [...colWidths];
+    nextWidths[colIndex] = round1(Math.max(0.5, widthMm));
+    const newInnerW = round1(nextWidths.reduce((a, b) => a + b, 0));
+    return {
+      ...elem,
+      tableColWidths: nextWidths,
+      width: round1(newInnerW + pad.left + pad.right),
+    };
+  }
+
   return {
     ...elem,
-    tableColWidths: colWidths,
-    width: round1(colWidths.reduce((a, b) => a + b, 0) + pad.left + pad.right),
+    tableColWidths: resizeTrackKeepingTotal(colWidths, colIndex, widthMm),
+    width: elem.width,
+  };
+}
+
+/** 在现有元素高度内均分行高 */
+export function equalizeTableRowHeights(elem: TemplateElement): TemplateElement {
+  const rows = getTableRows(elem);
+  const innerH = getTableInnerSizeMm(elem).height;
+  return {
+    ...elem,
+    tableRowHeights: scaleTracksToExactTotal(
+      Array.from({ length: rows }, () => innerH / rows),
+      innerH
+    ),
+    height: elem.height,
+  };
+}
+
+/** 在现有元素宽度内均分列宽 */
+export function equalizeTableColWidths(elem: TemplateElement): TemplateElement {
+  const cols = getTableCols(elem);
+  const innerW = getTableInnerSizeMm(elem).width;
+  return {
+    ...elem,
+    tableColWidths: scaleTracksToExactTotal(
+      Array.from({ length: cols }, () => innerW / cols),
+      innerW
+    ),
+    width: elem.width,
   };
 }
 
diff --git a/src/utils.ts b/src/utils.ts
index 7ac0eca..652c7c6 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -30,6 +30,21 @@ export const VARIABLE_MAPPING_ROW_INDEX_LABEL = '数据序号';
 /** 粘贴副本时相对原位置的偏移 (mm) */
 export const PASTE_ELEMENT_OFFSET_MM = 2;
 
+/** 在标签画布上居中放置元素（mm，保留 1 位小数） */
+export function centerElementOnLabel(
+  labelWidth: number,
+  labelHeight: number,
+  elementWidth: number,
+  elementHeight: number
+): { x: number; y: number } {
+  const x = Math.round(((labelWidth - elementWidth) / 2) * 10) / 10;
+  const y = Math.round(((labelHeight - elementHeight) / 2) * 10) / 10;
+  return {
+    x: Math.max(0, x),
+    y: Math.max(0, y),
+  };
+}
+
 /** 深拷贝元素并生成新 id，用于复制/粘贴 */
 export function cloneTemplateElementsForPaste(
   elements: TemplateElement[],