diff --git a/adapters/redis_cache.py b/adapters/redis_cache.py
index 866d08a..4af573c 100644
--- a/adapters/redis_cache.py
+++ b/adapters/redis_cache.py
@@ -22,10 +22,10 @@ class RedisResponseCache:
 
     Args:
         redis: 异步 Redis 客户端实例（duck-typed，需支持 get/set 方法）。
-        ttl_s: 缓存过期时间（秒）。
+        ttl_s: 缓存过期时间（秒）。None 表示永不过期。
     """
 
-    def __init__(self, redis: Any, ttl_s: int) -> None:
+    def __init__(self, redis: Any, ttl_s: int | None) -> None:
         self._redis = redis
         self._ttl_s = ttl_s
 
@@ -86,6 +86,9 @@ class RedisResponseCache:
         try:
             key = self._build_key(model, messages)
             value = json.dumps(dataclasses.asdict(response), ensure_ascii=False)
-            await self._redis.set(key, value, ex=self._ttl_s)
+            if self._ttl_s:
+                await self._redis.set(key, value, ex=self._ttl_s)
+            else:
+                await self._redis.set(key, value)
         except Exception:
             logger.warning("Redis 缓存写入失败，跳过缓存")
diff --git a/main.py b/main.py
index 21be78b..5ed49d0 100644
--- a/main.py
+++ b/main.py
@@ -85,9 +85,12 @@ def _build_adapters(settings: InfraSettings, embed_cfg: dict) -> _Adapters:
     cache = None
     if settings.redis_url:
         try:
+            import redis.asyncio as aioredis
             from adapters.redis_cache import RedisResponseCache
 
-            cache = RedisResponseCache(redis_url=settings.redis_url, ttl=settings.redis_cache_ttl)
+            redis_client = aioredis.from_url(settings.redis_url, decode_responses=True)
+            ttl_s = settings.redis_cache_ttl if settings.redis_cache_ttl > 0 else None
+            cache = RedisResponseCache(redis=redis_client, ttl_s=ttl_s)
         except Exception:
             logger.warning("Redis 缓存不可用，降级为无缓存模式")