diff --git a/affinity.go b/affinity.go
new file mode 100644
index 0000000..91b4558
--- /dev/null
+++ b/affinity.go
@@ -0,0 +1,26 @@
+package gobridge
+
+import (
+	"context"
+	"hash/fnv"
+)
+
+type affinityKey struct{} // 用户提供的字符串 key，acquire 时 hash 到 worker 下标
+
+// WithAffinity 将亲和键写入 ctx，相同 key 始终路由到同一 worker 进程。
+//
+//	ctx = gobridge.WithAffinity(ctx, "user-42")
+//	gobridge.Invoke(ctx, pool, "method", ...)  // 同 key 始终走同一进程
+func WithAffinity(ctx context.Context, key string) context.Context {
+	return context.WithValue(ctx, affinityKey{}, key)
+}
+
+// workerIndexFor 根据 ctx 计算应使用的 worker 下标，无亲和键时返回 -1（交由轮询）。
+func workerIndexFor(ctx context.Context, n int) int {
+	if key, ok := ctx.Value(affinityKey{}).(string); ok && key != "" {
+		h := fnv.New32a()
+		h.Write([]byte(key))
+		return int(h.Sum32()) % n
+	}
+	return -1
+}
diff --git a/example/main.go b/example/main.go
index ea13d1a..facdf10 100644
--- a/example/main.go
+++ b/example/main.go
@@ -34,6 +34,7 @@ func main() {
 
 	demoPool(ctx, pool)
 	demoServer(ctx, script)
+	demoSession(ctx, script)
 }
 
 func demoPool(ctx context.Context, pool gobridge.Pool) {
@@ -172,6 +173,86 @@ func (s *goService) MakeUser(ctx context.Context, uid int) (User, error) {
 	return User{ID: uid, Name: fmt.Sprintf("user_%d", uid), Score: float64(uid) * 1.5}, nil
 }
 
+func demoSession(ctx context.Context, script string) {
+	fmt.Println("\n── Session 亲和示例（workers=2）─────────────────────────────────")
+
+	pool, err := gobridge.NewPool(script, gobridge.WithWorkers(2))
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer pool.Close()
+
+	// ── NewSession：三个 session，C 与 A 落在同一 worker，验证互不干扰 ───────
+	sessA := gobridge.NewSession(pool) // worker 1
+	sessB := gobridge.NewSession(pool) // worker 0
+	sessC := gobridge.NewSession(pool) // worker 1（与 A 同进程，不同 session_id）
+
+	msgA, err := gobridge.Invoke[string](ctx, sessA, "session_init", "A", 100)
+	if err != nil {
+		log.Fatal(err)
+	}
+	fmt.Println("A init:", msgA)
+
+	msgB, err := gobridge.Invoke[string](ctx, sessB, "session_init", "B", 200)
+	if err != nil {
+		log.Fatal(err)
+	}
+	fmt.Println("B init:", msgB)
+
+	msgC, err := gobridge.Invoke[string](ctx, sessC, "session_init", "C", 300)
+	if err != nil {
+		log.Fatal(err)
+	}
+	fmt.Println("C init:", msgC) // 应与 A 在同一 worker
+
+	// 对 A/B/C 各自做 step，验证三者状态完全独立
+	v, _ := gobridge.Invoke[int](ctx, sessA, "session_step", "A", 10)
+	fmt.Println("A step(+10) =", v) // 110
+	v, _ = gobridge.Invoke[int](ctx, sessA, "session_step", "A", 5)
+	fmt.Println("A step(+5)  =", v) // 115
+
+	v, _ = gobridge.Invoke[int](ctx, sessB, "session_step", "B", 50)
+	fmt.Println("B step(+50) =", v) // 250
+
+	v, _ = gobridge.Invoke[int](ctx, sessC, "session_step", "C", 99)
+	fmt.Println("C step(+99) =", v) // 399（与 A 同 worker 但不受影响）
+
+	rA, _ := gobridge.Invoke[map[string]any](ctx, sessA, "session_result", "A")
+	rB, _ := gobridge.Invoke[map[string]any](ctx, sessB, "session_result", "B")
+	rC, _ := gobridge.Invoke[map[string]any](ctx, sessC, "session_result", "C")
+	fmt.Printf("A result = %v\n", rA) // map[steps:[10 5] value:115]
+	fmt.Printf("B result = %v\n", rB) // map[steps:[50]   value:250]
+	fmt.Printf("C result = %v\n", rC) // map[steps:[99]   value:399]
+
+	// ── 全局变量测试：sessA 和 sessC 同 worker，共享进程级 counter ──────────
+	fmt.Println()
+	r, _ := gobridge.Invoke[string](ctx, sessA, "global_increment", 10)
+	fmt.Println("sessA +10:", r) // worker 1 counter = 10
+	r, _ = gobridge.Invoke[string](ctx, sessC, "global_increment", 5)
+	fmt.Println("sessC +5 :", r) // worker 1 counter = 15（与 sessA 共享）
+	r, _ = gobridge.Invoke[string](ctx, sessB, "global_increment", 99)
+	fmt.Println("sessB +99:", r) // worker 0 counter = 99（独立进程，从 0 开始）
+	r, _ = gobridge.Invoke[string](ctx, sessA, "global_get")
+	fmt.Println("sessA get:", r) // worker 1 counter = 15（不受 sessB 影响）
+
+	// ── WithAffinity：相同 key 跨调用始终路由同一 worker ────────────────────
+	fmt.Println()
+	for i := range 4 {
+		affinityCtx := gobridge.WithAffinity(ctx, "sticky-key")
+		msg, _ := gobridge.Invoke[string](affinityCtx, pool, "session_init",
+			fmt.Sprintf("aff-%d", i), i)
+		fmt.Printf("WithAffinity(sticky-key) #%d → %s\n", i, msg)
+	}
+
+	// ── 对照组：不带亲和，轮询分配给两个 worker ─────────────────────────────
+	fmt.Println()
+	for i := range 4 {
+		msg, _ := gobridge.Invoke[string](ctx, pool, "session_init",
+			fmt.Sprintf("rr-%d", i), i)
+		fmt.Printf("round-robin          #%d → %s\n", i, msg)
+	}
+}
+
 func demoServer(ctx context.Context, script string) {
 	fmt.Println("\n── Server 全双工示例 ─────────────────────────────────────────────")
 
diff --git a/example/worker.py b/example/worker.py
index 7e3fb4d..3cb981a 100644
--- a/example/worker.py
+++ b/example/worker.py
@@ -143,6 +143,45 @@ def get_user_via_go(uid: int) -> dict:
     return dataclasses.asdict(user)
 
 
+# ── Session 亲和示例 ──────────────────────────────────────────────────────────
+# _sessions 保存每个 session 的状态，key 由调用方提供
+_sessions: dict = {}
+
+# _global_counter 是进程级全局变量，同一 worker 的所有 session 共享
+_global_counter: int = 0
+
+
+@expose
+def global_increment(delta: int) -> str:
+    global _global_counter
+    _global_counter += delta
+    return f"[worker {worker_id}] counter = {_global_counter}"
+
+
+@expose
+def global_get() -> str:
+    return f"[worker {worker_id}] counter = {_global_counter}"
+
+
+@expose
+def session_init(session_id: str, value: int) -> str:
+    _sessions[session_id] = {"value": value, "steps": []}
+    return f"[worker {worker_id}] session {session_id} init with {value}"
+
+
+@expose
+def session_step(session_id: str, delta: int) -> int:
+    s = _sessions[session_id]
+    s["value"] += delta
+    s["steps"].append(delta)
+    return s["value"]
+
+
+@expose
+def session_result(session_id: str) -> dict:
+    return _sessions.pop(session_id)
+
+
 if __name__ == "__main__":
     run()
     print("worker_id", worker_id)
diff --git a/pool.go b/pool.go
index a91c96c..aa84121 100644
--- a/pool.go
+++ b/pool.go
@@ -210,7 +210,18 @@ func (p *pool) bindHandler(name string, fn reflect.Value) {
 }
 
 func (p *pool) acquire(ctx context.Context) (net.Conn, *worker, error) {
-	idx := p.idx.Add(1) % uint64(len(p.workers))
+	n := uint64(len(p.workers))
+	if n == 0 {
+		return nil, nil, fmt.Errorf("gobridge: pool has no workers")
+	}
+
+	var idx uint64
+	if i := workerIndexFor(ctx, int(n)); i >= 0 {
+		idx = uint64(i) % n // 防御：ctx 可能来自不同 pool
+	} else {
+		idx = p.idx.Add(1) % n
+	}
+
 	w := p.workers[idx]
 	conn, err := w.acquire(ctx)
 	return conn, w, err
diff --git a/session.go b/session.go
new file mode 100644
index 0000000..62c3f1d
--- /dev/null
+++ b/session.go
@@ -0,0 +1,51 @@
+package gobridge
+
+import (
+	"context"
+	"net"
+)
+
+// singleWorkerPool 是 Pool 的包装，所有请求固定路由到同一个 worker 进程。
+type singleWorkerPool struct {
+	pool      *pool
+	workerIdx int
+}
+
+// NewSession 返回一个固定到某个 worker 进程的 Pool 视图。
+// 通过该 Pool 发起的所有 Invoke 调用始终路由到同一 Python 进程，
+// 适用于多次调用之间需要共享 Python 侧状态的场景。
+//
+//	session := gobridge.NewSession(pool)
+//	gobridge.Invoke(ctx, session, "init", arg)
+//	gobridge.Invoke(ctx, session, "next_step")  // 与上一行走同一进程
+func NewSession(p Pool) Pool {
+	inner, ok := p.(*pool)
+	if !ok {
+		// 已经是 session 或其他实现，直接返回
+		return p
+	}
+	n := uint64(len(inner.workers))
+	if n == 0 {
+		return p
+	}
+	idx := inner.idx.Add(1) % n
+	return &singleWorkerPool{pool: inner, workerIdx: int(idx)}
+}
+
+func (s *singleWorkerPool) acquire(ctx context.Context) (net.Conn, *worker, error) {
+	idx := s.workerIdx % len(s.pool.workers)
+	w := s.pool.workers[idx]
+	conn, err := w.acquire(ctx)
+	return conn, w, err
+}
+
+// Close 不关闭底层 pool，session 不拥有 pool 的生命周期。
+func (s *singleWorkerPool) Close() {}
+
+func (s *singleWorkerPool) nextReqID() uint64 {
+	return s.pool.nextReqID()
+}
+
+func (s *singleWorkerPool) callbackDispatch(ctx context.Context, msg Message) (any, string) {
+	return s.pool.callbackDispatch(ctx, msg)
+}