diff --git a/backend/services/rag-indexer-service/src/main/java/com/datamate/rag/indexer/application/KnowledgeBaseService.java b/backend/services/rag-indexer-service/src/main/java/com/datamate/rag/indexer/application/KnowledgeBaseService.java
index b9f7f26..4ffbbc2 100644
--- a/backend/services/rag-indexer-service/src/main/java/com/datamate/rag/indexer/application/KnowledgeBaseService.java
+++ b/backend/services/rag-indexer-service/src/main/java/com/datamate/rag/indexer/application/KnowledgeBaseService.java
@@ -35,7 +35,9 @@ import org.springframework.transaction.annotation.Transactional;
 import org.springframework.util.StringUtils;
 
 import java.util.Collections;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 import java.util.Optional;
 
 /**
@@ -47,6 +49,8 @@ import java.util.Optional;
 @Service
 @RequiredArgsConstructor
 public class KnowledgeBaseService {
+    private static final String RELATIVE_PATH_KEY = "relativePath";
+    private static final String PATH_SEPARATOR = "/";
     private final KnowledgeBaseRepository knowledgeBaseRepository;
     private final RagFileRepository ragFileRepository;
     private final ApplicationEventPublisher eventPublisher;
@@ -146,6 +150,12 @@ public class KnowledgeBaseService {
             ragFile.setKnowledgeBaseId(knowledgeBase.getId());
             ragFile.setFileId(fileInfo.id());
             ragFile.setFileName(fileInfo.fileName());
+            String relativePath = normalizeRelativePath(fileInfo.relativePath());
+            if (StringUtils.hasText(relativePath)) {
+                Map<String, Object> metadata = new HashMap<>();
+                metadata.put(RELATIVE_PATH_KEY, relativePath);
+                ragFile.setMetadata(metadata);
+            }
             ragFile.setStatus(FileStatus.UNPROCESSED);
             return ragFile;
         }).toList();
@@ -153,6 +163,17 @@ public class KnowledgeBaseService {
         eventPublisher.publishEvent(new DataInsertedEvent(knowledgeBase, request));
     }
 
+    private String normalizeRelativePath(String relativePath) {
+        if (!StringUtils.hasText(relativePath)) {
+            return "";
+        }
+        String normalized = relativePath.replace("\\", PATH_SEPARATOR).trim();
+        while (normalized.startsWith(PATH_SEPARATOR)) {
+            normalized = normalized.substring(1);
+        }
+        return normalized;
+    }
+
     public PagedResponse<RagFile> listFiles(String knowledgeBaseId, RagFileReq request) {
         IPage<RagFile> page = new Page<>(request.getPage(), request.getSize());
         request.setKnowledgeBaseId(knowledgeBaseId);
@@ -222,4 +243,4 @@ public class KnowledgeBaseService {
         });
         return searchResults;
     }
-}
\ No newline at end of file
+}
diff --git a/backend/services/rag-indexer-service/src/main/java/com/datamate/rag/indexer/interfaces/dto/AddFilesReq.java b/backend/services/rag-indexer-service/src/main/java/com/datamate/rag/indexer/interfaces/dto/AddFilesReq.java
index 65a642f..30f340d 100644
--- a/backend/services/rag-indexer-service/src/main/java/com/datamate/rag/indexer/interfaces/dto/AddFilesReq.java
+++ b/backend/services/rag-indexer-service/src/main/java/com/datamate/rag/indexer/interfaces/dto/AddFilesReq.java
@@ -21,6 +21,6 @@ public class AddFilesReq {
     private String delimiter;
     private List<FileInfo> files;
 
-    public record FileInfo(String id, String fileName) {
+    public record FileInfo(String id, String fileName, String relativePath) {
     }
 }
diff --git a/frontend/src/pages/KnowledgeBase/Detail/KnowledgeBaseDetail.tsx b/frontend/src/pages/KnowledgeBase/Detail/KnowledgeBaseDetail.tsx
index ff46c5f..4e34da1 100644
--- a/frontend/src/pages/KnowledgeBase/Detail/KnowledgeBaseDetail.tsx
+++ b/frontend/src/pages/KnowledgeBase/Detail/KnowledgeBaseDetail.tsx
@@ -57,14 +57,19 @@ type KBFileRow = KBFile & {
   fileCount?: number;
 };
 
-const normalizePath = (value?: string) => (value ?? "").replace(/\\/g, "/");
+const PATH_SEPARATOR = "/";
+const RELATIVE_PATH_KEY = "relativePath";
+const normalizePath = (value?: string) =>
+  (value ?? "").replace(/\\/g, PATH_SEPARATOR);
 
 const normalizePrefix = (value?: string) => {
   const trimmed = normalizePath(value).replace(/^\/+/, "").trim();
   if (!trimmed) {
     return "";
   }
-  return trimmed.endsWith("/") ? trimmed : `${trimmed}/`;
+  return trimmed.endsWith(PATH_SEPARATOR)
+    ? trimmed
+    : `${trimmed}${PATH_SEPARATOR}`;
 };
 
 const splitRelativePath = (fullPath: string, prefix: string) => {
@@ -72,7 +77,17 @@ const splitRelativePath = (fullPath: string, prefix: string) => {
     return [];
   }
   const remainder = fullPath.slice(prefix.length);
-  return remainder.split("/").filter(Boolean);
+  return remainder.split(PATH_SEPARATOR).filter(Boolean);
+};
+
+const resolveFileRelativePath = (file: KBFile) => {
+  const metadata = file?.metadata as Record<string, unknown> | undefined;
+  const metadataPath =
+    metadata && typeof metadata[RELATIVE_PATH_KEY] === "string"
+      ? String(metadata[RELATIVE_PATH_KEY])
+      : "";
+  const rawPath = metadataPath || file.fileName || file.name || "";
+  return normalizePath(rawPath).replace(/^\/+/, "");
 };
 
 const KnowledgeBaseDetailPage: React.FC = () => {
@@ -196,9 +211,11 @@ const KnowledgeBaseDetailPage: React.FC = () => {
       return;
     }
     const trimmed = currentPrefix.replace(/\/$/, "");
-    const parts = trimmed.split("/").filter(Boolean);
+    const parts = trimmed.split(PATH_SEPARATOR).filter(Boolean);
     parts.pop();
-    const parentPrefix = parts.length ? `${parts.join("/")}/` : "";
+    const parentPrefix = parts.length
+      ? `${parts.join(PATH_SEPARATOR)}${PATH_SEPARATOR}`
+      : "";
     setFilePrefix(parentPrefix);
   };
 
@@ -210,7 +227,7 @@ const KnowledgeBaseDetailPage: React.FC = () => {
     const directoryPrefix = normalizePrefix(`${currentPrefix}${directoryName}`);
     const targetIds = allFiles
       .filter((file) => {
-        const fullPath = normalizePath(file.fileName || file.name);
+        const fullPath = resolveFileRelativePath(file);
         return fullPath.startsWith(directoryPrefix);
       })
       .map((file) => file.id);
@@ -245,7 +262,7 @@ const KnowledgeBaseDetailPage: React.FC = () => {
     const fileItems: KBFileRow[] = [];
 
     allFiles.forEach((file) => {
-      const fullPath = normalizePath(file.fileName || file.name);
+      const fullPath = resolveFileRelativePath(file);
       if (!fullPath) {
         return;
       }
@@ -278,10 +295,11 @@ const KnowledgeBaseDetailPage: React.FC = () => {
         return;
       }
 
+      const displayName = file.fileName || leafName;
       fileItems.push({
         ...file,
-        name: leafName,
-        displayName: leafName,
+        name: displayName,
+        displayName,
         fullPath,
       });
     });
diff --git a/frontend/src/pages/KnowledgeBase/components/AddDataDialog.tsx b/frontend/src/pages/KnowledgeBase/components/AddDataDialog.tsx
index 7f635e6..a738ac0 100644
--- a/frontend/src/pages/KnowledgeBase/components/AddDataDialog.tsx
+++ b/frontend/src/pages/KnowledgeBase/components/AddDataDialog.tsx
@@ -26,19 +26,20 @@ export default function AddDataDialog({ knowledgeBase, onDataAdded }) {
 
   const [selectedFilesMap, setSelectedFilesMap] = useState({});
 
+  const PATH_SEPARATOR = "/";
   const normalizePath = (value?: string) =>
-    (value ?? "").replace(/\\/g, "/");
+    (value ?? "").replace(/\\/g, PATH_SEPARATOR);
 
-  const resolveRelativeFileName = (file: DatasetFile) => {
+  const resolveRelativePath = (file: DatasetFile) => {
     const normalizedName = normalizePath(file.fileName);
-    if (normalizedName.includes("/")) {
+    if (normalizedName.includes(PATH_SEPARATOR)) {
       return normalizedName.replace(/^\/+/, "");
     }
 
     const rawPath = normalizePath(file.path || file.filePath);
     const datasetId = String(file.datasetId || "");
     if (rawPath && datasetId) {
-      const marker = `/${datasetId}/`;
+      const marker = `${PATH_SEPARATOR}${datasetId}${PATH_SEPARATOR}`;
       const index = rawPath.lastIndexOf(marker);
       if (index >= 0) {
         const relative = rawPath
@@ -50,7 +51,7 @@ export default function AddDataDialog({ knowledgeBase, onDataAdded }) {
       }
     }
 
-    const fallbackName = rawPath.split("/").pop();
+    const fallbackName = rawPath.split(PATH_SEPARATOR).pop();
     return fallbackName || file.fileName;
   };
 
@@ -158,7 +159,8 @@ export default function AddDataDialog({ knowledgeBase, onDataAdded }) {
       const requestData = {
         files: Object.values(selectedFilesMap).map((file) => ({
           id: String(file.id),
-          fileName: resolveRelativeFileName(file as DatasetFile),
+          fileName: (file as DatasetFile).fileName,
+          relativePath: resolveRelativePath(file as DatasetFile),
         })),
         processType: newKB.processType,
         chunkSize: Number(newKB.chunkSize), // 确保是数字类型