diff --git a/python/sglang/srt/managers/scheduler.py b/python/sglang/srt/managers/scheduler.py
index fd1390a53..6c324b297 100644
--- a/python/sglang/srt/managers/scheduler.py
+++ b/python/sglang/srt/managers/scheduler.py
@@ -606,6 +606,7 @@ class Scheduler(
             or self.tp_worker.model_runner.mamba2_config is not None
         )
 
+        self.sliding_window_size = None
         if self.is_hybrid_swa:
             self.sliding_window_size = self.tp_worker.sliding_window_size
             self.full_tokens_per_layer, self.swa_tokens_per_layer = (
@@ -635,6 +636,7 @@ class Scheduler(
             pp_rank=self.pp_rank,
             pp_size=self.pp_size,
             chunked_prefill_size=server_args.chunked_prefill_size,
+            sliding_window_size=self.sliding_window_size,
         )
 
         if (
@@ -648,9 +650,7 @@ class Scheduler(
             else:
                 from sglang.srt.mem_cache.chunk_cache import SWAChunkCache
 
-                self.tree_cache = SWAChunkCache(
-                    params, sliding_window_size=self.sliding_window_size
-                )
+                self.tree_cache = SWAChunkCache(params)
         else:
 
             if envs.SGLANG_EXPERIMENTAL_CPP_RADIX_TREE.get():
@@ -669,9 +669,7 @@ class Scheduler(
             elif self.is_hybrid_swa:
                 from sglang.srt.mem_cache.swa_radix_cache import SWARadixCache
 
-                self.tree_cache = SWARadixCache(
-                    params=params, sliding_window_size=self.sliding_window_size
-                )
+                self.tree_cache = SWARadixCache(params=params)
             elif self.is_hybrid_ssm:
                 from sglang.srt.mem_cache.mamba_radix_cache import MambaRadixCache
 
diff --git a/python/sglang/srt/mem_cache/cache_init_params.py b/python/sglang/srt/mem_cache/cache_init_params.py
index 7f6111f80..7b1b4a7d6 100644
--- a/python/sglang/srt/mem_cache/cache_init_params.py
+++ b/python/sglang/srt/mem_cache/cache_init_params.py
@@ -31,3 +31,5 @@ class CacheInitParams:
     pp_size: int = 1
 
     chunked_prefill_size: Optional[int] = None
+
+    sliding_window_size: Optional[int] = None
diff --git a/python/sglang/srt/mem_cache/chunk_cache.py b/python/sglang/srt/mem_cache/chunk_cache.py
index 75f545166..87f88c7c6 100644
--- a/python/sglang/srt/mem_cache/chunk_cache.py
+++ b/python/sglang/srt/mem_cache/chunk_cache.py
@@ -90,11 +90,11 @@ class ChunkCache(BasePrefixCache):
 class SWAChunkCache(ChunkCache):
     """ChunkCache with support for sliding window attention."""
 
-    def __init__(self, params: CacheInitParams, sliding_window_size: int):
+    def __init__(self, params: CacheInitParams):
         assert isinstance(params.token_to_kv_pool_allocator, SWATokenToKVPoolAllocator)
         super().__init__(params)
 
-        self.sliding_window_size = sliding_window_size
+        self.sliding_window_size = params.sliding_window_size
         self.chunked_prefill_size = params.chunked_prefill_size
 
     def supports_swa(self) -> bool:
diff --git a/python/sglang/srt/mem_cache/swa_radix_cache.py b/python/sglang/srt/mem_cache/swa_radix_cache.py
index fceb83a3a..8148e8c40 100644
--- a/python/sglang/srt/mem_cache/swa_radix_cache.py
+++ b/python/sglang/srt/mem_cache/swa_radix_cache.py
@@ -333,7 +333,7 @@ class LRUList:
 
 
 class SWARadixCache(BasePrefixCache):
-    def __init__(self, params: CacheInitParams, sliding_window_size: int):
+    def __init__(self, params: CacheInitParams):
         assert isinstance(params.token_to_kv_pool_allocator, SWATokenToKVPoolAllocator)
         self.req_to_token_pool = params.req_to_token_pool
         self.token_to_kv_pool_allocator = params.token_to_kv_pool_allocator
@@ -361,7 +361,7 @@ class SWARadixCache(BasePrefixCache):
         if params.enable_metrics:
             self.init_metrics_collector()
 
-        self.sliding_window_size = sliding_window_size
+        self.sliding_window_size = params.sliding_window_size
         self.reset()
 
     ##### Public API #####
diff --git a/test/registered/radix_cache/test_swa_unittest.py b/test/registered/radix_cache/test_swa_unittest.py
index 63548401b..deb0bd2c0 100644
--- a/test/registered/radix_cache/test_swa_unittest.py
+++ b/test/registered/radix_cache/test_swa_unittest.py
@@ -127,8 +127,8 @@ class TestSWA(unittest.TestCase):
                 token_to_kv_pool_allocator=allocator,
                 disable=False,
                 page_size=page_size,
+                sliding_window_size=sliding_window_size,
             ),
-            sliding_window_size=sliding_window_size,
         )
 
         # test
@@ -264,8 +264,8 @@ class TestSWA(unittest.TestCase):
                 page_size=page_size,
                 disable=False,
                 is_eagle=True,
+                sliding_window_size=sliding_window_size,
             ),
-            sliding_window_size=sliding_window_size,
         )
 
         # test