diff --git a/public/locales/en.json b/public/locales/en.json
index ea4938e..f71fdfb 100644
--- a/public/locales/en.json
+++ b/public/locales/en.json
@@ -79,11 +79,12 @@
   "tree.desc": "Tree desc",
   "tree.export": "Export",
   "tree.firstid": "First id",
-  "tree.vars": "Variable Definition",
+  "tree.vars": "Define Variables",
   "tree.vars.name": "name",
   "tree.vars.invalidName": "Invalid variable name",
   "tree.vars.desc": "description",
-  "tree.vars.imports": "Variable References",
+  "tree.vars.imports": "Import Variables",
+  "tree.vars.subtree": "Subtree Variables",
 
   "regnode.input": "Input: ",
   "regnode.output": "Output: ",
diff --git a/public/locales/zh.json b/public/locales/zh.json
index dedb7b1..8358596 100644
--- a/public/locales/zh.json
+++ b/public/locales/zh.json
@@ -79,11 +79,12 @@
   "tree.desc": "说明",
   "tree.export": "导出",
   "tree.firstid": "起始标识",
-  "tree.vars": "变量定义",
+  "tree.vars": "定义变量",
   "tree.vars.name": "变量名",
   "tree.vars.invalidName": "变量名不合法",
   "tree.vars.desc": "变量说明",
-  "tree.vars.imports": "变量引用",
+  "tree.vars.imports": "导入变量",
+  "tree.vars.subtree": "子树变量",
 
   "regnode.input": "输入：",
   "regnode.output": "输出：",
diff --git a/sample/vars/test-subtree.json b/sample/vars/test-subtree.json
index 77abdc5..2139cb5 100644
--- a/sample/vars/test-subtree.json
+++ b/sample/vars/test-subtree.json
@@ -4,8 +4,15 @@
   "firstid": 1,
   "export": true,
   "declare": {
-    "imports": [],
-    "vars": []
+    "imports": [
+      "vars/declare-core.json"
+    ],
+    "vars": [
+      {
+        "name": "test",
+        "desc": "测试"
+      }
+    ]
   },
   "root": {
     "id": 1,
diff --git a/src/components/inspector.tsx b/src/components/inspector.tsx
index 89c57f9..23c3ec9 100644
--- a/src/components/inspector.tsx
+++ b/src/components/inspector.tsx
@@ -40,7 +40,7 @@ import {
   isNodeArgOptional,
   isValidVariableName,
   isVariadic,
-  loadImportedVars,
+  loadVarDef,
 } from "../misc/b3util";
 import { Hotkey, isMacos } from "../misc/keys";
 import { mergeClassNames } from "../misc/util";
@@ -65,7 +65,7 @@ const TreeInspector: FC = () => {
   // set form values
   useEffect(() => {
     const data = workspace.editingTree.data;
-    loadImportedVars(data.declare.imports);
+    loadVarDef(data.declare.imports);
     form.resetFields();
     form.setFieldValue("name", data.name);
     form.setFieldValue("desc", data.desc);
@@ -73,6 +73,7 @@ const TreeInspector: FC = () => {
     form.setFieldValue("firstid", data.firstid);
     form.setFieldValue("declare.vars", data.declare?.vars);
     form.setFieldValue("declare.imports", data.declare?.imports);
+    form.setFieldValue("declare.subtree", data.declare?.subtree);
   }, [workspace.editingTree]);
 
   // auto complete for subtree
@@ -231,6 +232,71 @@ const TreeInspector: FC = () => {
               )}
             </Form.List>
           </>
+          {workspace.editingTree.data.declare.subtree.length > 0 && (
+            <>
+              <Divider orientation="left">
+                <h4>{t("tree.vars.subtree")}</h4>
+              </Divider>
+              <Form.List name="declare.subtree">
+                {(vars) => (
+                  <div style={{ display: "flex", flexDirection: "column", rowGap: 0 }}>
+                    {vars.map((v, idx, arr) => (
+                      <Flex key={v.key} gap={4}>
+                        <Space.Compact
+                          className="b3-inspector-vars-item"
+                          style={{ width: "100%", marginBottom: 0, paddingRight: 18 }}
+                        >
+                          <Form.Item noStyle name={[v.name, "id"]}>
+                            <div
+                              style={{
+                                display: "flex",
+                                alignItems: "center",
+                                paddingLeft: "8px",
+                                paddingRight: "8px",
+                                maxWidth: "60px",
+                                minWidth: "60px",
+                                borderTopLeftRadius: idx === 0 ? "4px" : 0,
+                                borderBottomLeftRadius: idx === arr.length - 1 ? "4px" : 0,
+                                borderLeft: "1px solid #3d506c",
+                                borderTop: "1px solid #3d506c",
+                                borderBottom: idx === arr.length - 1 ? "1px solid #3d506c" : "none",
+                              }}
+                            >
+                              <AimOutlined />
+                              <span style={{ marginLeft: 4 }}>0</span>
+                            </div>
+                          </Form.Item>
+                          <Form.Item noStyle name={[v.name, "name"]}>
+                            <Input
+                              disabled={true}
+                              placeholder={t("tree.vars.name")}
+                              style={{
+                                borderRadius: "0",
+                                borderTop: "1px solid #3d506c",
+                                borderBottom: idx === arr.length - 1 ? "1px solid #3d506c" : "none",
+                              }}
+                            />
+                          </Form.Item>
+                          <Form.Item noStyle name={[v.name, "desc"]}>
+                            <Input
+                              disabled={true}
+                              placeholder={t("tree.vars.desc")}
+                              style={{
+                                borderTopRightRadius: idx === 0 ? "4px" : 0,
+                                borderBottomRightRadius: idx === arr.length - 1 ? "4px" : 0,
+                                borderTop: "1px solid #3d506c",
+                                borderBottom: idx === arr.length - 1 ? "1px solid #3d506c" : "none",
+                              }}
+                            />
+                          </Form.Item>
+                        </Space.Compact>
+                      </Flex>
+                    ))}
+                  </div>
+                )}
+              </Form.List>
+            </>
+          )}
           <>
             <Divider orientation="left">
               <h4>{t("tree.vars.imports")}</h4>
diff --git a/src/contexts/workspace-context.ts b/src/contexts/workspace-context.ts
index d8c6d7c..2b0eca6 100644
--- a/src/contexts/workspace-context.ts
+++ b/src/contexts/workspace-context.ts
@@ -7,6 +7,7 @@ import { create } from "zustand";
 import { NodeDef } from "../behavior3/src/behavior3";
 import { ImportDef, NodeModel, TreeGraphData, TreeModel, VarDef } from "../misc/b3type";
 import * as b3util from "../misc/b3util";
+import { loadSubtreeVarDef } from "../misc/b3util";
 import { message } from "../misc/hooks";
 import i18n from "../misc/i18n";
 import Path from "../misc/path";
@@ -128,6 +129,7 @@ export type EditTree = {
     declare: {
       imports: ImportDef[];
       vars: VarDef[];
+      subtree: VarDef[];
     };
   };
 };
@@ -521,6 +523,7 @@ export const useWorkspace = create<WorkspaceStore>((set, get) => ({
             declare: {
               vars: editting.declare.vars,
               imports: editting.declare.imports,
+              subtree: loadSubtreeVarDef(editting.data),
             },
           },
         },
@@ -679,6 +682,7 @@ export const useWorkspace = create<WorkspaceStore>((set, get) => ({
           declare: {
             imports: editor.declare.imports,
             vars: editor.declare.vars,
+            subtree: loadSubtreeVarDef(editor.data),
           },
         },
       },
diff --git a/src/misc/b3util.ts b/src/misc/b3util.ts
index 6addaf4..3786613 100644
--- a/src/misc/b3util.ts
+++ b/src/misc/b3util.ts
@@ -687,11 +687,11 @@ export const isTreeFile = (path: string) => {
   return path.toLocaleLowerCase().endsWith(".json");
 };
 
-export const loadImportedVars = (imports: ImportDef[]) => {
-  for (const importDef of imports) {
+export const loadVarDef = (list: ImportDef[]) => {
+  for (const entry of list) {
     // TODO: check file date
     // TODO: use cache
-    if (importDef.vars.length) {
+    if (entry.vars.length) {
       continue;
     }
     const filter: Map<string, boolean> = new Map();
@@ -701,14 +701,17 @@ export const loadImportedVars = (imports: ImportDef[]) => {
         return;
       }
       filter.set(path, true);
-      const model: TreeModel = readTree(`${workdir}/${path}`);
-      model.declare?.vars?.forEach((v) => vars.push(v));
-      model.declare?.imports?.forEach((v) => load(v));
-      console.log("load imported vars:", path);
+      try {
+        const model: TreeModel = readTree(`${workdir}/${path}`);
+        model.declare?.vars?.forEach((v) => vars.push(v));
+        model.declare?.imports?.forEach((v) => load(v));
+      } catch (e) {
+        alertError(`parsing error: ${path}`);
+      }
     };
-    load(importDef.path);
+    load(entry.path);
     filter.clear();
-    importDef.vars = vars
+    entry.vars = vars
       .filter((v) => {
         if (!filter.has(v.name)) {
           filter.set(v.name, true);
@@ -719,3 +722,28 @@ export const loadImportedVars = (imports: ImportDef[]) => {
       .sort((a, b) => a.name.localeCompare(b.name));
   }
 };
+
+export const loadSubtreeVarDef = (data: TreeGraphData) => {
+  const list: ImportDef[] = [];
+  const traverse = (v: TreeGraphData) => {
+    if (v.path) {
+      list.push({ path: v.path, vars: [] });
+    }
+    if (v.children) {
+      v.children.forEach(traverse);
+    }
+  };
+  traverse(data);
+  loadVarDef(list);
+  const filter: Map<string, boolean> = new Map();
+  const result: VarDef[] = [];
+  list.forEach((entry) => {
+    entry.vars.forEach((v) => {
+      if (!filter.has(v.name)) {
+        filter.set(v.name, true);
+        result.push(v);
+      }
+    });
+  });
+  return result;
+};