diff --git a/docs/cleaner-user-scope-fix.md b/docs/cleaner-user-scope-fix.md
new file mode 100644
index 0000000..d9df7d7
--- /dev/null
+++ b/docs/cleaner-user-scope-fix.md
@@ -0,0 +1,272 @@
+# CleanerPage User Scope Fix
+
+**Issue**: User users were affecting other users' data when using "取消" and "确认删除" buttons
+
+**Date**: 2026-03-03
+**Branch**: `fix/cleaner-user-scope`
+
+---
+
+## Problem Analysis
+
+### Bug Description
+
+For **User type (non-Admin)** users:
+1. The table shows only materials assigned to the current user (filtered by `filteredResults`)
+2. Clicking "取消" (Uncheck All) was unchecking **ALL** materials in `validationResults`, including invisible ones
+3. Clicking "确认删除" (Confirm Deletion) processed **ALL** materials in `validationResults`, not just visible ones
+4. This caused User A to delete User B's materials that User A never saw!
+
+### Root Causes
+
+#### 1. "取消" Button (Line 420)
+```typescript
+// ❌ WRONG: Clears ALL selected items
+onClick={() => setSelectedItems(new Set())}
+```
+
+#### 2. `handleConfirmDeletion` Function (Line 165)
+```typescript
+// ❌ WRONG: Iterates ALL validation results
+for (const result of validationResults) {
+  // Processes items user can't even see!
+}
+```
+
+### Data Flow
+
+```mermaid
+graph TB
+    subgraph "Backend"
+        A[validationResults<br/>1000 items] --> B[User Filter<br/>currentUsername]
+    end
+
+    subgraph "Frontend Display"
+        B --> C[filteredResults<br/>100 items visible]
+        C --> D[Table Display]
+    end
+
+    subgraph "Bug Behavior (BEFORE FIX)"
+        E[取消 Button] --> F[Clears selectedItems<br/>for ALL 1000 items ❌]
+        G[确认删除 Button] --> H[Processes ALL 1000 items ❌]
+        H --> I[Deletes User B's data ❌]
+    end
+
+    subgraph "Fixed Behavior (AFTER FIX)"
+        E2[取消 Button] --> F2[Clears only visible<br/>100 items ✅]
+        G2[确认删除 Button] --> H2[Processes only<br/>100 items ✅]
+        H2 --> I2[Only affects User A ✅]
+    end
+```
+
+---
+
+## Solution
+
+### Fix 1: "取消" Button - Only Uncheck Visible Items
+
+**File**: `src/renderer/src/pages/CleanerPage.tsx:419-432`
+
+```typescript
+<button
+  onClick={() => {
+    // Only uncheck items that are visible in filteredResults
+    const visibleCodes = new Set(filteredResults.map((r) => r.materialCode))
+    setSelectedItems((prev) => {
+      const newSet = new Set(prev)
+      for (const code of visibleCodes) {
+        newSet.delete(code)
+      }
+      return newSet
+    })
+  }}
+  className="text-xs bg-white border border-slate-300 text-slate-700 px-2.5 py-1.5 rounded shadow-sm hover:bg-slate-50 flex items-center gap-1"
+>
+  <Square size={14} className="text-slate-400" /> 取消
+</button>
+```
+
+**What Changed**:
+- Before: `setSelectedItems(new Set())` - clears everything
+- After: Iterates through `filteredResults` and removes only visible items from `selectedItems`
+- Preserves selections for items not currently visible (e.g., other users' data)
+
+### Fix 2: `handleConfirmDeletion` - Only Process Visible Items (Non-Admin)
+
+**File**: `src/renderer/src/pages/CleanerPage.tsx:158-222`
+
+```typescript
+const handleConfirmDeletion = async () => {
+  // For non-admin users, only process visible filtered results
+  // For admin users, process all validation results
+  const resultsToProcess = isAdmin ? validationResults : filteredResults
+
+  if (resultsToProcess.length === 0) return alert('没有可处理的数据')
+
+  const materialsToUpsert: { materialCode: string; managerName: string }[] = []
+  const materialsToDelete: string[] = []
+  const missingManager: string[] = []
+
+  for (const result of resultsToProcess) {
+    // ... rest of processing logic
+  }
+  // ...
+}
+```
+
+**What Changed**:
+- Before: `for (const result of validationResults)` - processes all 1000 items
+- After: `for (const result of resultsToProcess)` where:
+  - `Admin` → processes `validationResults` (all items)
+  - `User` → processes only `filteredResults` (visible items)
+
+---
+
+## Testing Scenarios
+
+### Scenario 1: User Unchecks Own Data Only
+
+**Setup**:
+- User A logs in (non-Admin)
+- 100 materials visible (assigned to User A)
+- 900 materials invisible (assigned to other users)
+- All 1000 materials are initially checked
+
+**Actions**:
+1. User A clicks "取消"
+2. Table shows all checkboxes unchecked
+
+**Expected**:
+- ✅ User A's 100 materials are unchecked
+- ✅ Other users' 900 materials **remain checked** (not affected)
+
+**Verification**:
+```typescript
+// Before fix: selectedItems.size === 0
+// After fix: selectedItems.size === 900 (other users' items still checked)
+```
+
+### Scenario 2: User Confirms Deletion
+
+**Setup**:
+- User A logs in (non-Admin)
+- User A unchecks 50 of their 100 materials
+- 50 items checked (User A's)
+- 900 items checked (other users')
+
+**Actions**:
+1. User A clicks "确认删除"
+2. Confirm dialog shows: "写入/更新 50 条记录"
+
+**Expected**:
+- ✅ Only User A's 50 materials are upserted to database
+- ✅ Other users' 900 materials are **NOT touched**
+- ✅ No materials are deleted (since other users' items aren't processed)
+
+### Scenario 3: Admin Behavior Unchanged
+
+**Setup**:
+- Admin logs in
+- All 1000 materials visible
+- All filtered by selected managers
+
+**Actions**:
+1. Admin clicks "取消" → all visible items unchecked
+2. Admin clicks "确认删除" → processes all filtered items
+
+**Expected**:
+- ✅ Admin behavior unchanged (can manage all data)
+- ✅ Admin can still filter by managers and process filtered results
+
+---
+
+## Security & Scope Implications
+
+### Before Fix (Vulnerability)
+```mermaid
+flowchart LR
+    UserA[User A] --> Sees[Sees 100 items]
+    UserB[User B] --> Sees2[Sees 900 items]
+    Sees --> Clicks[Clicks 取消 + 确认删除]
+    Clicks --> Deletes[Deletes ALL 1000 items ❌]
+    Deletes --> Impact[User B loses data ❌]
+```
+
+### After Fix (Secure)
+```mermaid
+flowchart LR
+    UserA[User A] --> Sees[Sees 100 items]
+    UserB[User B] --> Sees2[Sees 900 items]
+    Sees --> Clicks[Clicks 取消 + 确认删除]
+    Clicks --> Deletes[Deletes 100 items ✅]
+    Sees2 --> Independent[User B's data independent ✅]
+    Deletes --> Safe[User scope isolation ✅]
+```
+
+---
+
+## Code Changes Summary
+
+### File: `src/renderer/src/pages/CleanerPage.tsx`
+
+| Line | Change | Description |
+|------|--------|-------------|
+| 419-432 | Modified "取消" button | Only uncheck visible filteredResults |
+| 158-222 | Modified `handleConfirmDeletion` | Use `resultsToProcess` based on `isAdmin` |
+
+### Variables Used
+
+- `validationResults`: All materials from backend (1000 items)
+- `filteredResults`: Materials after user/manager filtering (100 items for User A)
+- `selectedItems`: Set of checked material codes
+- `isAdmin`: Boolean, true for Admin users
+- `currentUsername`: Current logged-in username
+
+---
+
+## Verification Steps
+
+1. **Test as User A**:
+   ```bash
+   # Login as user1
+   npm run dev
+   # Navigate to CleanerPage
+   # Verify only user1's materials are visible
+   # Click "取消" → only visible items unchecked
+   # Check selectedItems size = other users' checked items
+   ```
+
+2. **Test as User B**:
+   ```bash
+   # Login as user2
+   # Verify user1's changes didn't affect user2's data
+   # All user2's materials should still be intact
+   ```
+
+3. **Test as Admin**:
+   ```bash
+   # Login as admin
+   # Verify can still see and manage all materials
+   # "取消" and "确认删除" work on all filtered results
+   ```
+
+---
+
+## Related Files
+
+- **Implementation**: `src/renderer/src/pages/CleanerPage.tsx`
+- **Related**: `src/main/ipc/validation-handler.ts` (backend matching logic)
+- **Related**: `docs/user-override-match-feature.md` (user override matching)
+
+---
+
+## Future Improvements
+
+1. **Add Confirmation Dialog for Scope**: Show user how many items will be affected
+2. **Add Audit Logging**: Log which user modified which materials
+3. **Add Warning for Large Operations**: Warn if user is about to delete many items
+4. **Backend Validation**: Add backend check to prevent cross-user data modification
+
+---
+
+**Document End**
diff --git a/src/renderer/src/pages/CleanerPage.tsx b/src/renderer/src/pages/CleanerPage.tsx
index 8e9145f..8fad336 100644
--- a/src/renderer/src/pages/CleanerPage.tsx
+++ b/src/renderer/src/pages/CleanerPage.tsx
@@ -156,13 +156,17 @@ const CleanerPage: React.FC = () => {
   }
 
   const handleConfirmDeletion = async () => {
-    if (validationResults.length === 0) return alert('没有可处理的数据')
+    // For non-admin users, only process visible filtered results
+    // For admin users, process all validation results
+    const resultsToProcess = isAdmin ? validationResults : filteredResults
+
+    if (resultsToProcess.length === 0) return alert('没有可处理的数据')
 
     const materialsToUpsert: { materialCode: string; managerName: string }[] = []
     const materialsToDelete: string[] = []
     const missingManager: string[] = []
 
-    for (const result of validationResults) {
+    for (const result of resultsToProcess) {
       if (!result.materialCode?.trim()) continue
 
       const code = result.materialCode.trim()
@@ -417,7 +421,17 @@ const CleanerPage: React.FC = () => {
               <CheckSquare size={14} className="text-blue-600" /> 全选
             </button>
             <button
-              onClick={() => setSelectedItems(new Set())}
+              onClick={() => {
+                // Only uncheck items that are visible in filteredResults
+                const visibleCodes = new Set(filteredResults.map((r) => r.materialCode))
+                setSelectedItems((prev) => {
+                  const newSet = new Set(prev)
+                  for (const code of visibleCodes) {
+                    newSet.delete(code)
+                  }
+                  return newSet
+                })
+              }}
               className="text-xs bg-white border border-slate-300 text-slate-700 px-2.5 py-1.5 rounded shadow-sm hover:bg-slate-50 flex items-center gap-1"
             >
               <Square size={14} className="text-slate-400" /> 取消