diff --git a/app/apps/page.tsx b/app/apps/page.tsx
index 49a998c..7200483 100644
--- a/app/apps/page.tsx
+++ b/app/apps/page.tsx
@@ -62,6 +62,7 @@ import { useCurrentUser } from "@/hooks/useCurrentUser";
 import { checkSuperAdmin } from "@/lib/clientPermissions";
 import WorkflowEditor from "./components/WorkflowEditor";
 import { syncFormToWorkflow } from "@/lib/workflowUtils";
+import { resolveAutoSelectDatasets } from "@/lib/appDatasets";
 import { WorkflowConfig } from "@/types/workflow";
 import { DEFAULT_LLM_MODEL_CODE, type LlmModelOption } from "@/lib/llmModels";
 
@@ -466,8 +467,7 @@ export default function AppsPage() {
       settings: app.settings || {},
       is_default: app.is_default || false,
     });
-    // 如果 dataset_ids 为空，则自动选择知识库为 true，否则为 false
-    setAutoSelectDatasets(datasetIds.length === 0);
+    setAutoSelectDatasets(resolveAutoSelectDatasets(app.settings, datasetIds));
 
     setDialogOpen(true);
   }, []);
@@ -482,12 +482,18 @@ export default function AppsPage() {
     try {
       setSubmitting(true);
 
-      const workflow = syncFormToWorkflow({ ...formData }, editingApp?.settings?.workflow, datasets);
+      const workflow = syncFormToWorkflow(
+        { ...formData },
+        editingApp?.settings?.workflow,
+        datasets
+      );
       const submitData = {
         ...formData,
+        dataset_ids: autoSelectDatasets ? [] : formData.dataset_ids,
         settings: {
           ...formData.settings,
           workflow,
+          auto_select_datasets: autoSelectDatasets,
         },
       };
 
@@ -514,7 +520,7 @@ export default function AppsPage() {
     } finally {
       setSubmitting(false);
     }
-  }, [formData, editingApp, loadApps, datasets]);
+  }, [formData, autoSelectDatasets, editingApp, loadApps, datasets]);
 
   // 提交应用审核（draft/rejected → pending_review；建即 draft，仅 owner 可测）
   const handleSubmitAppReview = useCallback(
@@ -926,10 +932,10 @@ export default function AppsPage() {
                           <div className="text-sm">
                             <div className="flex items-center gap-4">
                               {/* 数据集为 0 不显示。
-                                  0 不是"没有知识库"——`dataset_ids` 为空时后端走
+                                  空 `dataset_ids` 加上自动选择开关（settings.auto_select_datasets，
+                                  未存过则默认开）时，后端走
                                   `kb_classifier_service.select_relevant_datasets(user_id=...)`，
-                                  在该用户有权限的**所有**知识库里智能选（auto_select_kb）。
-                                  所以 0 表示的是默认行为，把它显示成 0 会读成"这个员工没知识"。*/}
+                                  在该用户有权限的知识库里智能选。把它显示成 0 会读成"这个员工没知识"。*/}
                               {(app.dataset_ids?.length || 0) > 0 && (
                                 <div className="flex items-center gap-2">
                                   <span className="text-muted-foreground">{t("datasets")}</span>
@@ -1364,13 +1370,14 @@ export default function AppsPage() {
                     onCheckedChange={(checked) => {
                       const isChecked = checked === true;
                       setAutoSelectDatasets(isChecked);
-                      // 如果勾选了自动选择知识库，清空所有已选择的知识库
-                      if (isChecked) {
-                        setFormData({
-                          ...formData,
-                          dataset_ids: [],
-                        });
-                      }
+                      setFormData({
+                        ...formData,
+                        dataset_ids: isChecked ? [] : formData.dataset_ids,
+                        settings: {
+                          ...formData.settings,
+                          auto_select_datasets: isChecked,
+                        },
+                      });
                     }}
                   />
                   <label
diff --git a/lib/appDatasets.ts b/lib/appDatasets.ts
new file mode 100644
index 0000000..a162294
--- /dev/null
+++ b/lib/appDatasets.ts
@@ -0,0 +1,19 @@
+/**
+ * 应用「自动选择知识库」开关。
+ *
+ * 不能只用 dataset_ids 是否为空来推断：取消勾选后如果不选具体库，保存的仍是空数组，
+ * 下次打开会被当成「自动选择」。开关本身存在 apps.settings.auto_select_datasets。
+ */
+export function resolveAutoSelectDatasets(
+  settings?: Record<string, unknown> | null,
+  datasetIds?: string[] | null
+): boolean {
+  if (datasetIds && datasetIds.length > 0) {
+    return false;
+  }
+  const stored = settings?.auto_select_datasets;
+  if (typeof stored === "boolean") {
+    return stored;
+  }
+  return true;
+}
diff --git a/test/appAutoSelectDatasets.test.ts b/test/appAutoSelectDatasets.test.ts
new file mode 100644
index 0000000..f4cddee
--- /dev/null
+++ b/test/appAutoSelectDatasets.test.ts
@@ -0,0 +1,32 @@
+import assert from "node:assert/strict";
+import { readFileSync } from "node:fs";
+import { test } from "node:test";
+import { resolveAutoSelectDatasets } from "../lib/appDatasets.ts";
+
+test("绑了知识库时一定不是自动选择", () => {
+  assert.equal(resolveAutoSelectDatasets({ auto_select_datasets: true }, ["ds-1"]), false);
+  assert.equal(resolveAutoSelectDatasets(undefined, ["ds-1"]), false);
+});
+
+test("未绑知识库时以 settings 里存下的开关为准", () => {
+  assert.equal(resolveAutoSelectDatasets({ auto_select_datasets: false }, []), false);
+  assert.equal(resolveAutoSelectDatasets({ auto_select_datasets: true }, []), true);
+  assert.equal(resolveAutoSelectDatasets({ auto_select_datasets: false }, undefined), false);
+});
+
+test("存量应用没存过开关时，空 dataset_ids 仍视为自动选择", () => {
+  assert.equal(resolveAutoSelectDatasets({}, []), true);
+  assert.equal(resolveAutoSelectDatasets(undefined, []), true);
+  assert.equal(resolveAutoSelectDatasets(null, null), true);
+});
+
+test("应用编辑页保存并回填自动选择知识库开关", () => {
+  const src = readFileSync(new URL("../app/apps/page.tsx", import.meta.url), "utf8");
+  assert.match(src, /resolveAutoSelectDatasets/);
+  assert.match(src, /auto_select_datasets:\s*autoSelectDatasets/);
+  assert.doesNotMatch(
+    src,
+    /setAutoSelectDatasets\(datasetIds\.length === 0\)/,
+    "不能再用空 dataset_ids 推断开关，否则取消勾选记不住"
+  );
+});