diff --git a/packages/preset-dumi/src/theme/loader.ts b/packages/preset-dumi/src/theme/loader.ts
index bda391b2ef..7cf63b92ce 100644
--- a/packages/preset-dumi/src/theme/loader.ts
+++ b/packages/preset-dumi/src/theme/loader.ts
@@ -84,7 +84,7 @@ function detectTheme() {
 export default async () => {
   if (!cache || process.env.NODE_ENV === 'test') {
     const [name = process.env.DUMI_THEME || FALLBACK_THEME] = detectTheme();
-    const theme = name.startsWith('/') ? name : `${name}/src`;
+    const theme = path.isAbsolute(name) ? name : `${name}/src`;
     const modulePath = winPath(path.resolve(ctx.umi.paths.absNodeModulesPath, theme));
     const builtinPath = path.join(modulePath, 'builtins');
     const components = fs.existsSync(builtinPath)