diff --git a/migrations/0001_add_series.sql b/migrations/0001_add_series.sql
new file mode 100644
index 0000000..4b9c4cf
--- /dev/null
+++ b/migrations/0001_add_series.sql
@@ -0,0 +1,14 @@
+CREATE TABLE series (
+  id INTEGER PRIMARY KEY AUTOINCREMENT,
+  name TEXT NOT NULL UNIQUE COLLATE NOCASE,
+  slug TEXT NOT NULL UNIQUE,
+  description TEXT,
+  created_at DATETIME DEFAULT CURRENT_TIMESTAMP
+);
+
+ALTER TABLE posts ADD COLUMN series_id INTEGER REFERENCES series(id) ON DELETE SET NULL;
+ALTER TABLE posts ADD COLUMN series_weight INTEGER;
+
+CREATE INDEX idx_posts_series_order ON posts(series_id, series_weight, published_at, id);
+
+INSERT OR IGNORE INTO settings (key, value) VALUES ('alias.series', '系列');
diff --git a/schema.sql b/schema.sql
index 0755e31..5b4b114 100644
--- a/schema.sql
+++ b/schema.sql
@@ -1,5 +1,6 @@
 DROP TABLE IF EXISTS post_tags;
 DROP TABLE IF EXISTS posts;
+DROP TABLE IF EXISTS series;
 DROP TABLE IF EXISTS tags;
 DROP TABLE IF EXISTS categories;
 DROP TABLE IF EXISTS pages;
@@ -20,6 +21,14 @@ CREATE TABLE categories (
   slug TEXT NOT NULL UNIQUE
 );
 
+CREATE TABLE series (
+  id INTEGER PRIMARY KEY AUTOINCREMENT,
+  name TEXT NOT NULL UNIQUE COLLATE NOCASE,
+  slug TEXT NOT NULL UNIQUE,
+  description TEXT,
+  created_at DATETIME DEFAULT CURRENT_TIMESTAMP
+);
+
 CREATE TABLE posts (
   id INTEGER PRIMARY KEY AUTOINCREMENT,
   slug TEXT NOT NULL UNIQUE,
@@ -27,13 +36,18 @@ CREATE TABLE posts (
   content TEXT NOT NULL,
   author_id INTEGER NOT NULL,
   category_id INTEGER,
+  series_id INTEGER,
+  series_weight INTEGER,
   published_at DATETIME DEFAULT CURRENT_TIMESTAMP,
   updated_at DATETIME DEFAULT CURRENT_TIMESTAMP,
   cover TEXT,
   FOREIGN KEY (author_id) REFERENCES users(id),
-  FOREIGN KEY (category_id) REFERENCES categories(id) ON DELETE SET NULL
+  FOREIGN KEY (category_id) REFERENCES categories(id) ON DELETE SET NULL,
+  FOREIGN KEY (series_id) REFERENCES series(id) ON DELETE SET NULL
 );
 
+CREATE INDEX idx_posts_series_order ON posts(series_id, series_weight, published_at, id);
+
 CREATE TABLE pages (
   id INTEGER PRIMARY KEY AUTOINCREMENT,
   slug TEXT NOT NULL UNIQUE,
@@ -102,6 +116,7 @@ INSERT INTO settings (key, value) VALUES
 ('alias.post', '文章'),
 ('alias.category', '分类'),
 ('alias.tag', '标签'),
+('alias.series', '系列'),
 ('alias.page', '页面'),
 ('site.title', 'BlogFlare'),
 ('site.description', 'A high-performance blog powered by Cloudflare D1, R2, and KV.'),