diff --git a/config/config2.example.yaml b/config/config2.example.yaml
index 74d2ab880..fd4409f97 100644
--- a/config/config2.example.yaml
+++ b/config/config2.example.yaml
@@ -86,6 +86,7 @@ exp_pool:
 role_zero:
   enable_longterm_memory: false # Whether to use long-term memory. Default is `false`.
   longterm_memory_persist_path: .role_memory_data # The directory to save data.
+  memory_k: 200 # The capacity of short-term memory.
 
 azure_tts_subscription_key: "YOUR_SUBSCRIPTION_KEY"
 azure_tts_region: "eastus"
diff --git a/metagpt/configs/role_zero_config.py b/metagpt/configs/role_zero_config.py
index ada5afb63..21d50a3ac 100644
--- a/metagpt/configs/role_zero_config.py
+++ b/metagpt/configs/role_zero_config.py
@@ -6,3 +6,4 @@ from metagpt.utils.yaml_model import YamlModel
 class RoleZeroConfig(YamlModel):
     enable_longterm_memory: bool = Field(default=False, description="Whether to use long-term memory.")
     longterm_memory_persist_path: str = Field(default=".role_memory_data", description="The directory to save data.")
+    memory_k: int = Field(default=200, description="The capacity of short-term memory.")
diff --git a/metagpt/roles/di/role_zero.py b/metagpt/roles/di/role_zero.py
index fda29add9..b202fd3cc 100644
--- a/metagpt/roles/di/role_zero.py
+++ b/metagpt/roles/di/role_zero.py
@@ -179,11 +179,12 @@ class RoleZero(Role):
         """
 
         if self.config.role_zero.enable_longterm_memory:
+            # Use config.role_zero to initialize long-term memory
             self.rc.memory = RoleZeroLongTermMemory(
                 **self.rc.memory.model_dump(),
                 persist_path=self.config.role_zero.longterm_memory_persist_path,
                 collection_name=self.name.replace(" ", ""),
-                memory_k=self.memory_k,
+                memory_k=self.config.role_zero.memory_k,
             )
             logger.info(f"Long-term memory set for role '{self.name}'")