diff --git a/frontend/components/dataflow/ConnectionSetupModal.tsx b/frontend/components/dataflow/ConnectionSetupModal.tsx
index b23f7f4f..5ed118ef 100644
--- a/frontend/components/dataflow/ConnectionSetupModal.tsx
+++ b/frontend/components/dataflow/ConnectionSetupModal.tsx
@@ -171,22 +171,49 @@ export const ConnectionSetupModal: React.FC<ConnectionSetupModalProps> = ({
           break;
       }
 
-      // API 호출을 위한 관계 데이터 준비
+      // 선택된 컬럼들 추출
+      const selectedColumnsData = connection.selectedColumnsData || {};
+      const tableNames = Object.keys(selectedColumnsData);
+      const fromTable = tableNames[0];
+      const toTable = tableNames[1];
+
+      const fromColumns = selectedColumnsData[fromTable]?.columns || [];
+      const toColumns = selectedColumnsData[toTable]?.columns || [];
+
+      if (fromColumns.length === 0 || toColumns.length === 0) {
+        toast.error("선택된 컬럼이 없습니다.");
+        return;
+      }
+
+      toast.loading("관계를 생성하고 있습니다...", { id: "create-relationship" });
+
+      // 단일 관계 데이터 준비 (모든 선택된 컬럼 정보 포함)
       const relationshipData: Omit<TableRelationship, "relationshipId"> = {
         relationshipName: config.relationshipName,
         fromTableName: connection.fromNode.tableName,
-        fromColumnName: connection.fromColumn || "",
+        fromColumnName: fromColumns.join(","), // 여러 컬럼을 콤마로 구분
         toTableName: connection.toNode.tableName,
-        toColumnName: connection.toColumn || "",
+        toColumnName: toColumns.join(","), // 여러 컬럼을 콤마로 구분
         relationshipType: config.relationshipType,
         connectionType: config.connectionType,
         companyCode: companyCode,
-        settings: settings,
+        settings: {
+          ...settings,
+          multiColumnMapping: {
+            fromColumns: fromColumns,
+            toColumns: toColumns,
+            fromTable: selectedColumnsData[fromTable]?.displayName || fromTable,
+            toTable: selectedColumnsData[toTable]?.displayName || toTable,
+          },
+          isMultiColumn: fromColumns.length > 1 || toColumns.length > 1,
+          columnCount: {
+            from: fromColumns.length,
+            to: toColumns.length,
+          },
+        },
         isActive: "Y",
       };
 
-      toast.loading("관계를 생성하고 있습니다...", { id: "create-relationship" });
-
       // API 호출
       const createdRelationship = await DataFlowAPI.createRelationship(relationshipData);