diff --git a/frontend/components/screen/widgets/FlowWidget.tsx b/frontend/components/screen/widgets/FlowWidget.tsx
index 50ad0343..5564a14d 100644
--- a/frontend/components/screen/widgets/FlowWidget.tsx
+++ b/frontend/components/screen/widgets/FlowWidget.tsx
@@ -130,7 +130,7 @@ export function FlowWidget({
   const [stepData, setStepData] = useState<any[]>([]);
   const [stepDataColumns, setStepDataColumns] = useState<string[]>([]);
   const [stepDataLoading, setStepDataLoading] = useState(false);
-  const [selectedRows, setSelectedRows] = useState<Set<number>>(new Set());
+  const [selectedRows, setSelectedRows] = useState<Set<string>>(new Set()); // Primary Key 값으로 선택 관리
   const [columnLabels, setColumnLabels] = useState<Record<string, string>>({}); // 컬럼명 -> 라벨 매핑
 
   // 🆕 검색 필터 관련 상태
@@ -753,25 +753,35 @@ export function FlowWidget({
     }
   };
 
-  // 체크박스 토글
-  const toggleRowSelection = (rowIndex: number) => {
+  // Primary Key 컬럼명 (플로우 정의에서 가져오거나 기본값 id)
+  const primaryKeyColumn = flowData?.primaryKey || "id";
+
+  // 행의 Primary Key 값 가져오기
+  const getRowKey = useCallback((row: any): string => {
+    const keyValue = row[primaryKeyColumn] || row.id;
+    return String(keyValue);
+  }, [primaryKeyColumn]);
+
+  // 체크박스 토글 (Primary Key 기반)
+  const toggleRowSelection = (row: any) => {
     // 프리뷰 모드에서는 행 선택 차단
     if (isPreviewMode) {
       return;
     }
 
+    const rowKey = getRowKey(row);
     const newSelected = new Set(selectedRows);
-    if (newSelected.has(rowIndex)) {
-      newSelected.delete(rowIndex);
+    if (newSelected.has(rowKey)) {
+      newSelected.delete(rowKey);
     } else {
-      newSelected.add(rowIndex);
+      newSelected.add(rowKey);
     }
     setSelectedRows(newSelected);
 
-    // 선택된 데이터를 상위로 전달
-    const selectedData = Array.from(newSelected).map((index) => stepData[index]);
+    // 선택된 데이터를 상위로 전달 (stepData에서 선택된 행들 찾기)
+    const selectedData = stepData.filter((r) => newSelected.has(getRowKey(r)));
     console.log("🌊 FlowWidget - 체크박스 토글, 상위로 전달:", {
-      rowIndex,
+      rowKey,
       newSelectedSize: newSelected.size,
       selectedData,
       selectedStepId,
@@ -780,18 +790,18 @@ export function FlowWidget({
     onSelectedDataChange?.(selectedData, selectedStepId);
   };
 
-  // 전체 선택/해제
+  // 전체 선택/해제 (Primary Key 기반)
   const toggleAllRows = () => {
-    let newSelected: Set<number>;
+    let newSelected: Set<string>;
     if (selectedRows.size === stepData.length) {
       newSelected = new Set();
     } else {
-      newSelected = new Set(stepData.map((_, index) => index));
+      newSelected = new Set(stepData.map((row) => getRowKey(row)));
     }
     setSelectedRows(newSelected);
 
     // 선택된 데이터를 상위로 전달
-    const selectedData = Array.from(newSelected).map((index) => stepData[index]);
+    const selectedData = stepData.filter((row) => newSelected.has(getRowKey(row)));
     onSelectedDataChange?.(selectedData, selectedStepId);
   };
 
@@ -951,36 +961,41 @@ export function FlowWidget({
     return formatValue(value);
   }, []);
 
-  // 🆕 전체 선택 핸들러
+  // 🆕 전체 선택 핸들러 (Primary Key 기반)
   const handleSelectAll = useCallback((checked: boolean) => {
     if (checked) {
-      const allIndices = new Set(sortedDisplayData.map((_, idx) => idx));
-      setSelectedRows(allIndices);
+      const allKeys = new Set(sortedDisplayData.map((row) => getRowKey(row)));
+      setSelectedRows(allKeys);
+      // 선택된 데이터를 상위로 전달
+      onSelectedDataChange?.(sortedDisplayData, selectedStepId);
     } else {
       setSelectedRows(new Set());
+      onSelectedDataChange?.([], selectedStepId);
     }
-  }, [sortedDisplayData]);
+  }, [sortedDisplayData, getRowKey, onSelectedDataChange, selectedStepId]);
 
   // 🆕 행 클릭 핸들러
   const handleRowClick = useCallback((row: any) => {
     // 필요 시 행 클릭 로직 추가
   }, []);
 
-  // 🆕 체크박스 셀 렌더링
-  const renderCheckboxCell = useCallback((row: any, index: number) => {
+  // 🆕 체크박스 셀 렌더링 (Primary Key 기반)
+  // index 파라미터는 SingleTableWithSticky 인터페이스 호환을 위해 유지하지만 사용하지 않음
+  const renderCheckboxCell = useCallback((row: any, _index: number) => {
+    const rowKey = getRowKey(row);
     return (
       <Checkbox
-        checked={selectedRows.has(index)}
-        onCheckedChange={() => toggleRowSelection(index)}
+        checked={selectedRows.has(rowKey)}
+        onCheckedChange={() => toggleRowSelection(row)}
       />
     );
-  }, [selectedRows, toggleRowSelection]);
+  }, [selectedRows, toggleRowSelection, getRowKey]);
 
-  // 🆕 Excel 내보내기
+  // 🆕 Excel 내보내기 (Primary Key 기반)
   const exportToExcel = useCallback(() => {
     try {
       const exportData = selectedRows.size > 0 
-        ? sortedDisplayData.filter((_, idx) => selectedRows.has(idx))
+        ? sortedDisplayData.filter((row) => selectedRows.has(getRowKey(row)))
         : sortedDisplayData;
 
       if (exportData.length === 0) {
@@ -1010,13 +1025,13 @@ export function FlowWidget({
       console.error("Excel 내보내기 오류:", error);
       toast.error("Excel 내보내기에 실패했습니다.");
     }
-  }, [sortedDisplayData, selectedRows, stepDataColumns, columnLabels, flowName]);
+  }, [sortedDisplayData, selectedRows, stepDataColumns, columnLabels, flowName, getRowKey]);
 
   // 🆕 PDF 내보내기 (html2canvas 사용으로 한글 지원)
   const exportToPdf = useCallback(async () => {
     try {
       const exportData = selectedRows.size > 0 
-        ? sortedDisplayData.filter((_, idx) => selectedRows.has(idx))
+        ? sortedDisplayData.filter((row) => selectedRows.has(getRowKey(row)))
         : sortedDisplayData;
 
       if (exportData.length === 0) {
@@ -1175,13 +1190,13 @@ export function FlowWidget({
       console.error("PDF 내보내기 오류:", error);
       toast.error("PDF 내보내기에 실패했습니다.", { id: "pdf-export" });
     }
-  }, [sortedDisplayData, selectedRows, stepDataColumns, columnLabels, flowName]);
+  }, [sortedDisplayData, selectedRows, stepDataColumns, columnLabels, flowName, getRowKey]);
 
-  // 🆕 복사 기능
+  // 🆕 복사 기능 (Primary Key 기반)
   const handleCopy = useCallback(() => {
     try {
       const copyData = selectedRows.size > 0 
-        ? sortedDisplayData.filter((_, idx) => selectedRows.has(idx))
+        ? sortedDisplayData.filter((row) => selectedRows.has(getRowKey(row)))
         : [];
 
       if (copyData.length === 0) {
@@ -1203,7 +1218,7 @@ export function FlowWidget({
       console.error("복사 오류:", error);
       toast.error("복사에 실패했습니다.");
     }
-  }, [sortedDisplayData, selectedRows, stepDataColumns, columnLabels]);
+  }, [sortedDisplayData, selectedRows, stepDataColumns, columnLabels, getRowKey]);
 
   // 🆕 통합 검색 실행
   const executeGlobalSearch = useCallback((term: string) => {
@@ -1828,15 +1843,15 @@ export function FlowWidget({
                       <div
                         key={actualIndex}
                         className={`bg-card rounded-md border p-3 transition-colors ${
-                          selectedRows.has(actualIndex) ? "bg-primary/5 border-primary/30" : ""
+                          selectedRows.has(getRowKey(row)) ? "bg-primary/5 border-primary/30" : ""
                         }`}
                       >
                     {allowDataMove && (
                       <div className="mb-2 flex items-center justify-between border-b pb-2">
                         <span className="text-muted-foreground text-xs font-medium">선택</span>
                             <Checkbox
-                              checked={selectedRows.has(actualIndex)}
-                              onCheckedChange={() => toggleRowSelection(actualIndex)}
+                              checked={selectedRows.has(getRowKey(row))}
+                              onCheckedChange={() => toggleRowSelection(row)}
                             />
                       </div>
                     )}
@@ -1919,13 +1934,13 @@ export function FlowWidget({
                             return (
                       <TableRow
                                 key={`${group.groupKey}-${itemIndex}`}
-                                className={`h-16 transition-colors hover:bg-muted/50 ${selectedRows.has(actualIndex) ? "bg-primary/5" : ""}`}
+                                className={`h-16 transition-colors hover:bg-muted/50 ${selectedRows.has(getRowKey(row)) ? "bg-primary/5" : ""}`}
                       >
                         {allowDataMove && (
                                   <TableCell className="bg-background sticky left-0 z-10 border-b px-6 py-3 text-center">
                             <Checkbox
-                                      checked={selectedRows.has(actualIndex)}
-                                      onCheckedChange={() => toggleRowSelection(actualIndex)}
+                                      checked={selectedRows.has(getRowKey(row))}
+                                      onCheckedChange={() => toggleRowSelection(row)}
                             />
                           </TableCell>
                         )}