diff --git a/e2e/tests/auto-nav-sidebar-dir-convension.test.ts b/e2e/tests/auto-nav-sidebar-dir-convension.test.ts
index d9bf5c19c..05e3c25a8 100644
--- a/e2e/tests/auto-nav-sidebar-dir-convension.test.ts
+++ b/e2e/tests/auto-nav-sidebar-dir-convension.test.ts
@@ -112,4 +112,51 @@ test.describe('Auto nav and sidebar dir convention', async () => {
     );
     expect(contexts3.join(',')).toEqual(['context-index-in-meta'].join(','));
   });
+
+  test('/api/config/index.html /api/config/index /api/config should be the same page', async ({
+    page,
+  }) => {
+    async function getSidebarLength(): Promise<number> {
+      return (
+        (await page.$$(
+          `.rspress-sidebar .rspress-scrollbar > nav > section,
+      .rspress-sidebar .rspress-scrollbar > nav > a`,
+        )) ?? []
+      ).length;
+    }
+
+    async function isMenuItemActive(): Promise<boolean> {
+      const activeMenuItem = await page.$(
+        '.rspress-sidebar-collapse[class*="menuItemActive"]',
+      );
+      const content = await activeMenuItem?.textContent();
+      return content === 'index md convention';
+    }
+    // /api/config/index.html
+    await page.goto(
+      `http://localhost:${appPort}/guide/index-md-convention/index.html`,
+      {
+        waitUntil: 'networkidle',
+      },
+    );
+    expect(await getSidebarLength()).toBe(7);
+    expect(await isMenuItemActive()).toBe(true);
+
+    // /api/config/index
+    await page.goto(
+      `http://localhost:${appPort}/guide/index-md-convention/index`,
+      {
+        waitUntil: 'networkidle',
+      },
+    );
+    expect(await getSidebarLength()).toBe(7);
+    expect(await isMenuItemActive()).toBe(true);
+
+    // /api/config
+    await page.goto(`http://localhost:${appPort}/guide/index-md-convention`, {
+      waitUntil: 'networkidle',
+    });
+    expect(await getSidebarLength()).toBe(7);
+    expect(await isMenuItemActive()).toBe(true);
+  });
 });
diff --git a/packages/theme-default/src/components/Sidebar/index.tsx b/packages/theme-default/src/components/Sidebar/index.tsx
index 5ad723197..53dad7842 100644
--- a/packages/theme-default/src/components/Sidebar/index.tsx
+++ b/packages/theme-default/src/components/Sidebar/index.tsx
@@ -137,12 +137,13 @@ export function Sidebar(props: Props) {
   const removeLangPrefix = (path: string) => {
     return path.replace(langRoutePrefix, '');
   };
-  const activeMatcher = (path: string) =>
-    isActive(
+  const activeMatcher = (path: string) => {
+    return isActive(
       removeBase(removeLangPrefix(pathname)),
       removeLangPrefix(path),
       true,
     );
+  };
   const preloadLink = (link: string) => {
     const match = matchRoutes(routes, link);
     if (match?.length) {
diff --git a/packages/theme-default/src/index.ts b/packages/theme-default/src/index.ts
index 0731e42b1..cca2fe33a 100644
--- a/packages/theme-default/src/index.ts
+++ b/packages/theme-default/src/index.ts
@@ -1,9 +1,9 @@
 // eslint-disable-next-line @typescript-eslint/no-unused-vars
 import React from 'react';
-import { NotFoundLayout } from './layout/NotFountLayout';
-import { Layout } from './layout/Layout';
-import { HomeLayout } from './layout/HomeLayout';
 import { DocLayout } from './layout/DocLayout';
+import { HomeLayout } from './layout/HomeLayout';
+import { Layout } from './layout/Layout';
+import { NotFoundLayout } from './layout/NotFountLayout';
 import { setup } from './logic';
 
 export default {
diff --git a/packages/theme-default/src/logic/useSidebarData.ts b/packages/theme-default/src/logic/useSidebarData.ts
index 70ad48a96..9d393254e 100644
--- a/packages/theme-default/src/logic/useSidebarData.ts
+++ b/packages/theme-default/src/logic/useSidebarData.ts
@@ -1,12 +1,12 @@
+import { isEqualPath, useLocation, withBase } from '@rspress/runtime';
 import {
-  type NormalizedSidebarGroup,
-  type SidebarItem,
   type NormalizedSidebar,
+  type NormalizedSidebarGroup,
   type SidebarDivider,
+  type SidebarItem,
   addTrailingSlash,
 } from '@rspress/shared';
 import { useEffect, useState } from 'react';
-import { useLocation, withBase, isEqualPath } from '@rspress/runtime';
 import { useLocaleSiteData } from './useLocaleSiteData';
 
 interface SidebarData {
@@ -65,6 +65,7 @@ export const getSidebarGroupData = (
               currentPathname.startsWith(
                 // https://github.com/web-infra-dev/rspress/issues/360
                 // Ensure the other group name ends with `/` to avoid some unexpected results, for example, `/react-native` will match `/react`, that's not what we want
+                // FIXME: should parse url instead of add trailing slash
                 addTrailingSlash(withBase(otherGroupName)),
               )
             ) {
@@ -74,20 +75,42 @@ export const getSidebarGroupData = (
             }
           }
         }
-        const equalFunc = () =>
-          'link' in item &&
-          item.link !== '' &&
-          isEqualPath(withBase(item.link), currentPathname);
 
-        if ('items' in item) {
-          // If the current path is the same as the group link, return true
-          if (equalFunc()) {
+        const isLink = 'link' in item && item.link !== '';
+        const isDir = 'items' in item;
+
+        // 0. divider or section headers others return false
+
+        // 1. file link
+        if (!isDir && isLink) {
+          // 1.1 /api/config /api/config.html
+          if (isEqualPath(withBase(item.link), currentPathname)) {
+            return true;
+          }
+          // 1.2 /api/config/index /api/config/index.html
+          if (
+            currentPathname.includes('index') &&
+            isEqualPath(`${item.link}/index`, currentPathname)
+          ) {
+            return true;
+          }
+        }
+
+        // 2. dir
+        if (isDir) {
+          // 2.1 dir link (index convention)
+          if (
+            isLink &&
+            (isEqualPath(withBase(item.link), currentPathname) ||
+              isEqualPath(withBase(`${item.link}/index`), currentPathname))
+          ) {
             return true;
           }
+          // 2.2 dir recursive
           return item.items.some(i => match(i));
         }
 
-        return equalFunc();
+        return false;
       };
 
       return match(group);
diff --git a/packages/theme-default/src/logic/utils.ts b/packages/theme-default/src/logic/utils.ts
index 0dd7b92d8..2362b8423 100644
--- a/packages/theme-default/src/logic/utils.ts
+++ b/packages/theme-default/src/logic/utils.ts
@@ -1,9 +1,9 @@
-// eslint-disable-next-line @typescript-eslint/no-unused-vars
-import React from 'react';
-import htmr from 'htmr';
-import { parseDocument } from 'htmlparser2';
 import { isEqualPath } from '@rspress/runtime';
+import { parseDocument } from 'htmlparser2';
+import htmr from 'htmr';
 import { isNumber } from 'lodash-es';
+// eslint-disable-next-line @typescript-eslint/no-unused-vars
+import React from 'react';
 
 export function isActive(
   currentPath: string,
@@ -14,7 +14,10 @@ export function isActive(
     return false;
   }
   if (strict) {
-    return isEqualPath(currentPath, targetLink);
+    return (
+      isEqualPath(currentPath, targetLink) ||
+      isEqualPath(currentPath, `${targetLink}/index`)
+    );
   }
 
   return (