diff --git a/packages/core/src/config.ts b/packages/core/src/config.ts
index 2c722104..8644e0e5 100644
--- a/packages/core/src/config.ts
+++ b/packages/core/src/config.ts
@@ -48,7 +48,7 @@ const findConfig = (basePath: string): string | undefined => {
   return DEFAULT_EXTENSIONS.map((ext) => basePath + ext).find(fs.existsSync);
 };
 
-const resolveConfigPath = (root: string, customConfig?: string) => {
+const resolveConfigPath = (root: string, customConfig?: string): string => {
   if (customConfig) {
     const customConfigPath = isAbsolute(customConfig)
       ? customConfig
@@ -65,7 +65,7 @@ const resolveConfigPath = (root: string, customConfig?: string) => {
     return configFilePath;
   }
 
-  return undefined;
+  throw new Error(`${DEFAULT_CONFIG_NAME} not found`);
 };
 
 export async function loadConfig({
@@ -77,7 +77,7 @@ export async function loadConfig({
   path?: string;
   envMode?: string;
 }): Promise<RslibConfig> {
-  const configFilePath = resolveConfigPath(cwd, path)!;
+  const configFilePath = resolveConfigPath(cwd, path);
   const { content } = await loadRsbuildConfig({
     cwd: dirname(configFilePath),
     path: configFilePath,
diff --git a/packages/core/tests/config.test.ts b/packages/core/tests/config.test.ts
index 0a3c873e..adf02713 100644
--- a/packages/core/tests/config.test.ts
+++ b/packages/core/tests/config.test.ts
@@ -8,8 +8,8 @@ vi.mock('rslog');
 describe('Should load config file correctly', () => {
   test('Load config.js in cjs project', async () => {
     const fixtureDir = join(__dirname, 'fixtures/config/cjs');
-    const configDir = join(fixtureDir, 'rslib.config.js');
-    const config = await loadConfig({ cwd: configDir });
+    const configFilePath = join(fixtureDir, 'rslib.config.js');
+    const config = await loadConfig({ path: configFilePath });
     expect(config).toEqual({
       lib: [],
       source: {
@@ -18,15 +18,15 @@ describe('Should load config file correctly', () => {
         },
       },
       _privateMeta: {
-        configFilePath: configDir,
+        configFilePath,
       },
     });
   });
 
   test('Load config.mjs in cjs project', async () => {
     const fixtureDir = join(__dirname, 'fixtures/config/cjs');
-    const configDir = join(fixtureDir, 'rslib.config.mjs');
-    const config = await loadConfig({ cwd: configDir });
+    const configFilePath = join(fixtureDir, 'rslib.config.mjs');
+    const config = await loadConfig({ path: configFilePath });
     expect(config).toEqual({
       lib: [],
       source: {
@@ -35,15 +35,15 @@ describe('Should load config file correctly', () => {
         },
       },
       _privateMeta: {
-        configFilePath: configDir,
+        configFilePath,
       },
     });
   });
 
   test('Load config.ts in cjs project', async () => {
     const fixtureDir = join(__dirname, 'fixtures/config/cjs');
-    const configDir = join(fixtureDir, 'rslib.config.ts');
-    const config = await loadConfig({ cwd: configDir });
+    const configFilePath = join(fixtureDir, 'rslib.config.ts');
+    const config = await loadConfig({ path: configFilePath });
     expect(config).toEqual({
       lib: [],
       source: {
@@ -52,15 +52,15 @@ describe('Should load config file correctly', () => {
         },
       },
       _privateMeta: {
-        configFilePath: configDir,
+        configFilePath,
       },
     });
   });
 
   test('Load config.cjs with defineConfig in cjs project', async () => {
     const fixtureDir = join(__dirname, 'fixtures/config/cjs');
-    const configDir = join(fixtureDir, 'rslib.config.cjs');
-    const config = await loadConfig({ cwd: configDir });
+    const configFilePath = join(fixtureDir, 'rslib.config.cjs');
+    const config = await loadConfig({ path: configFilePath });
     expect(config).toEqual({
       lib: [],
       source: {
@@ -69,15 +69,15 @@ describe('Should load config file correctly', () => {
         },
       },
       _privateMeta: {
-        configFilePath: configDir,
+        configFilePath,
       },
     });
   });
 
   test('Load config.js in esm project', async () => {
     const fixtureDir = join(__dirname, 'fixtures/config/esm');
-    const configDir = join(fixtureDir, 'rslib.config.js');
-    const config = await loadConfig({ cwd: configDir });
+    const configFilePath = join(fixtureDir, 'rslib.config.js');
+    const config = await loadConfig({ path: configFilePath });
     expect(config).toEqual({
       lib: [],
       source: {
@@ -86,15 +86,15 @@ describe('Should load config file correctly', () => {
         },
       },
       _privateMeta: {
-        configFilePath: configDir,
+        configFilePath,
       },
     });
   });
 
   test('Load config.cjs in esm project', async () => {
     const fixtureDir = join(__dirname, 'fixtures/config/esm');
-    const configDir = join(fixtureDir, 'rslib.config.cjs');
-    const config = await loadConfig({ cwd: configDir });
+    const configFilePath = join(fixtureDir, 'rslib.config.cjs');
+    const config = await loadConfig({ path: configFilePath });
     expect(config).toEqual({
       lib: [],
       source: {
@@ -103,15 +103,15 @@ describe('Should load config file correctly', () => {
         },
       },
       _privateMeta: {
-        configFilePath: configDir,
+        configFilePath,
       },
     });
   });
 
   test('Load config.ts in esm project', async () => {
     const fixtureDir = join(__dirname, 'fixtures/config/esm');
-    const configDir = join(fixtureDir, 'rslib.config.ts');
-    const config = await loadConfig({ cwd: configDir });
+    const configFilePath = join(fixtureDir, 'rslib.config.ts');
+    const config = await loadConfig({ path: configFilePath });
     expect(config).toEqual({
       lib: [],
       source: {
@@ -120,16 +120,16 @@ describe('Should load config file correctly', () => {
         },
       },
       _privateMeta: {
-        configFilePath: configDir,
+        configFilePath,
       },
     });
   });
 
   test('Load config.mjs with defineConfig in esm project', async () => {
     const fixtureDir = join(__dirname, 'fixtures/config/esm');
-    const configDir = join(fixtureDir, 'rslib.config.mjs');
-    const config = await loadConfig({ cwd: configDir });
-    expect(config).toEqual({
+    const configFilePath = join(fixtureDir, 'rslib.config.mjs');
+    const config = await loadConfig({ path: configFilePath });
+    expect(config).toMatchObject({
       lib: [],
       source: {
         entry: {
@@ -137,7 +137,7 @@ describe('Should load config file correctly', () => {
         },
       },
       _privateMeta: {
-        configFilePath: configDir,
+        configFilePath,
       },
     });
   });