diff --git a/src/content/config.ts b/src/content/config.ts
index a5ac255..dc035c6 100644
--- a/src/content/config.ts
+++ b/src/content/config.ts
@@ -11,7 +11,19 @@ const postsCollection = defineCollection({
     image: z.string().optional().default(''),
     // Extended Settings
     lang: z.string().optional().default(''),
-    slug: z.string().optional().default(''),
+    slug: z.string()
+      .optional()
+      .default('')
+      .refine(
+        (slug) => {
+          if (!slug)
+            return true
+          return /^[\w\-]*$/.test(slug)
+        },
+        {
+          message: 'Slug can only contain letters, numbers, hyphens and underscores',
+        },
+      ),
     toc: z.boolean().optional().default(false),
     pin: z.boolean().optional().default(false),
     draft: z.boolean().optional().default(false),
diff --git a/src/pages/[lang]/index.astro b/src/pages/[lang]/index.astro
index 87d2755..def533c 100644
--- a/src/pages/[lang]/index.astro
+++ b/src/pages/[lang]/index.astro
@@ -21,7 +21,7 @@ const posts = await getPosts()
         <ul>
           {pinnedPosts.map(post => (
             <li>
-              <a href={`/${lang}/posts/${post.slug}/`}>
+              <a href={`/${lang}/posts/${post.data.slug || post.slug}/`}>
                 {post.data.title}
                 <time>({post.data.published.toISOString().split('T')[0]})</time>
               </a>
@@ -35,7 +35,7 @@ const posts = await getPosts()
       <ul>
         {posts.map(post => (
           <li>
-            <a href={`/${lang}/posts/${post.slug}/`}>
+            <a href={`/${lang}/posts/${post.data.slug || post.slug}/`}>
               {post.data.title}
               <time>({post.data.published.toISOString().split('T')[0]})</time>
             </a>
diff --git a/src/pages/[lang]/posts/[slug].astro b/src/pages/[lang]/posts/[slug].astro
index 1d1eae2..e65d6a7 100644
--- a/src/pages/[lang]/posts/[slug].astro
+++ b/src/pages/[lang]/posts/[slug].astro
@@ -1,13 +1,23 @@
 ---
 import { themeConfig } from '@/config'
 import Layout from '@/layouts/Layout.astro'
+import { checkSlugDuplication } from '@/utils/content.config'
 import { getCollection } from 'astro:content'
 
 export async function getStaticPaths() {
   const posts = await getCollection('posts')
+  
+  const duplicates = await checkSlugDuplication(posts)
+  if (duplicates.length > 0) {
+    throw new Error(`Slug conflicts found:\n${duplicates.join('\n')}`)
+  }
+
   return themeConfig.global.moreLocale.flatMap(lang =>
     posts.map(post => ({
-      params: { lang, slug: post.slug },
+      params: {
+        lang,
+        slug: post.data.slug || post.slug,
+      },
       props: { post },
     })),
   )
diff --git a/src/pages/[lang]/rss.xml.ts b/src/pages/[lang]/rss.xml.ts
index b6e511e..408cee3 100644
--- a/src/pages/[lang]/rss.xml.ts
+++ b/src/pages/[lang]/rss.xml.ts
@@ -65,7 +65,7 @@ export async function GET({ params }: APIContext) {
       pubDate: post.data.published,
       description: post.data.description || getExcerpt(post.body),
       // Generate absolute URL with language prefix
-      link: new URL(`${lang}/posts/${post.slug}/`, url).toString(),
+      link: new URL(`${lang}/posts/${post.data.slug || post.slug}/`, url).toString(),
       // Convert markdown content to HTML, allowing img tags
       content: post.body
         ? sanitizeHtml(parser.render(post.body), {
diff --git a/src/pages/[lang]/tags/[tags].astro b/src/pages/[lang]/tags/[tags].astro
index 3319886..aaac175 100644
--- a/src/pages/[lang]/tags/[tags].astro
+++ b/src/pages/[lang]/tags/[tags].astro
@@ -32,7 +32,7 @@ const allTags = await getAllTags()
     <ul>
       {posts.map(post => (
         <li>
-          <a href={`/${lang}/posts/${post.slug}/`}>{post.data.title}</a>
+          <a href={`/${lang}/posts/${post.data.slug || post.slug}/`}>{post.data.title}</a>
         </li>
       ))}
     </ul>
diff --git a/src/pages/index.astro b/src/pages/index.astro
index a28ceb8..0433832 100644
--- a/src/pages/index.astro
+++ b/src/pages/index.astro
@@ -13,7 +13,7 @@ const pinnedPosts = await getPinnedPosts()
         <ul>
           {pinnedPosts.map(post => (
             <li>
-              <a href={`/posts/${post.slug}/`}>
+              <a href={`/posts/${post.data.slug || post.slug}/`}>
                 {post.data.title}
                 <time>({post.data.published.toISOString().split('T')[0]})</time>
               </a>
@@ -27,7 +27,7 @@ const pinnedPosts = await getPinnedPosts()
       <ul>
         {posts.map(post => (
           <li>
-            <a href={`/posts/${post.slug}/`}>
+            <a href={`/posts/${post.data.slug || post.slug}/`}>
               {post.data.title}
               <time>({post.data.published.toISOString().split('T')[0]})</time>
             </a>
diff --git a/src/pages/posts/[slug].astro b/src/pages/posts/[slug].astro
index 7576075..da1714d 100644
--- a/src/pages/posts/[slug].astro
+++ b/src/pages/posts/[slug].astro
@@ -1,11 +1,20 @@
 ---
 import Layout from '@/layouts/Layout.astro'
+import { checkSlugDuplication } from '@/utils/content.config'
 import { getCollection } from 'astro:content'
 
 export async function getStaticPaths() {
   const posts = await getCollection('posts')
+  
+  const duplicates = await checkSlugDuplication(posts)
+  if (duplicates.length > 0) {
+    throw new Error(`Slug conflicts found:\n${duplicates.join('\n')}`)
+  }
+
   return posts.map(post => ({
-    params: { slug: post.slug },
+    params: {
+      slug: post.data.slug || post.slug,
+    },
     props: { post },
   }))
 }
diff --git a/src/pages/rss.xml.ts b/src/pages/rss.xml.ts
index 7cde56d..11a07e3 100644
--- a/src/pages/rss.xml.ts
+++ b/src/pages/rss.xml.ts
@@ -42,7 +42,7 @@ export async function GET() {
       pubDate: post.data.published,
       description: post.data.description || getExcerpt(post.body),
       // Generate absolute URL for post
-      link: new URL(`posts/${post.slug}/`, url).toString(),
+      link: new URL(`posts/${post.data.slug || post.slug}/`, url).toString(),
       // Convert markdown content to HTML, allowing img tags
       content: post.body
         ? sanitizeHtml(parser.render(post.body), {
diff --git a/src/pages/tags/[tags].astro b/src/pages/tags/[tags].astro
index 068dd92..4703bf9 100644
--- a/src/pages/tags/[tags].astro
+++ b/src/pages/tags/[tags].astro
@@ -28,7 +28,7 @@ const allTags = await getAllTags()
     <ul>
       {posts.map(post => (
         <li>
-          <a href={`/posts/${post.slug}/`}>{post.data.title}</a>
+          <a href={`/posts/${post.data.slug || post.slug}/`}>{post.data.title}</a>
         </li>
       ))}
     </ul>
diff --git a/src/utils/content.config.ts b/src/utils/content.config.ts
index 7cad6f6..ab37b0a 100644
--- a/src/utils/content.config.ts
+++ b/src/utils/content.config.ts
@@ -7,6 +7,31 @@ export type Post = CollectionEntry<'posts'>
 export type PostData = Post['data']
 export type PostsGroupByYear = Map<number, Post[]>
 
+// Check if the slug is duplicated under the same language.
+export async function checkSlugDuplication(posts: Post[]): Promise<string[]> {
+  const slugMap = new Map<string, Set<string>>() // Map<lang, Set<slug>>
+  const duplicates: string[] = []
+
+  posts.forEach((post) => {
+    const lang = post.data.lang || ''
+    const slug = post.data.slug || post.slug
+
+    if (!slugMap.has(lang)) {
+      slugMap.set(lang, new Set())
+    }
+
+    const slugSet = slugMap.get(lang)!
+    if (slugSet.has(slug)) {
+      duplicates.push(`Duplicate slug "${slug}" found in language "${lang || 'default'}"`)
+    }
+    else {
+      slugSet.add(slug)
+    }
+  })
+
+  return duplicates
+}
+
 // Get all posts except drafts (include pinned)
 export async function getPosts(lang?: string) {
   const defaultLocale = themeConfig.global.locale