diff --git a/libs/langchain/langchain/chat_models/baichuan.py b/libs/langchain/langchain/chat_models/baichuan.py
index 88c95fc4c3f..df48f926b3c 100644
--- a/libs/langchain/langchain/chat_models/baichuan.py
+++ b/libs/langchain/langchain/chat_models/baichuan.py
@@ -98,7 +98,7 @@ class ChatBaichuan(BaseChatModel):
 
     baichuan_api_base: str = Field(default=DEFAULT_API_BASE)
     """Baichuan custom endpoints"""
-    baichuan_api_key: Optional[str] = None
+    baichuan_api_key: Optional[SecretStr] = None
     """Baichuan API Key"""
     baichuan_secret_key: Optional[SecretStr] = None
     """Baichuan Secret Key"""
@@ -159,10 +159,12 @@ class ChatBaichuan(BaseChatModel):
             "BAICHUAN_API_BASE",
             DEFAULT_API_BASE,
         )
-        values["baichuan_api_key"] = get_from_dict_or_env(
-            values,
-            "baichuan_api_key",
-            "BAICHUAN_API_KEY",
+        values["baichuan_api_key"] = convert_to_secret_str(
+            get_from_dict_or_env(
+                values,
+                "baichuan_api_key",
+                "BAICHUAN_API_KEY",
+            )
         )
         values["baichuan_secret_key"] = convert_to_secret_str(
             get_from_dict_or_env(
@@ -254,12 +256,16 @@ class ChatBaichuan(BaseChatModel):
             url = f"{url}/stream"
         url = f"{url}/chat"
 
+        api_key = ""
+        if self.baichuan_api_key:
+            api_key = self.baichuan_api_key.get_secret_value()
+
         res = requests.post(
             url=url,
             timeout=self.request_timeout,
             headers={
                 "Content-Type": "application/json",
-                "Authorization": f"Bearer {self.baichuan_api_key}",
+                "Authorization": f"Bearer {api_key}",
                 "X-BC-Timestamp": str(timestamp),
                 "X-BC-Signature": _signature(
                     secret_key=self.baichuan_secret_key,
diff --git a/libs/langchain/tests/unit_tests/chat_models/test_baichuan.py b/libs/langchain/tests/unit_tests/chat_models/test_baichuan.py
index 1168f8dbeb3..93c4cbb91da 100644
--- a/libs/langchain/tests/unit_tests/chat_models/test_baichuan.py
+++ b/libs/langchain/tests/unit_tests/chat_models/test_baichuan.py
@@ -1,3 +1,5 @@
+from typing import cast
+
 import pytest
 from langchain_core.messages import (
     AIMessage,
@@ -9,8 +11,10 @@ from langchain_core.messages import (
     SystemMessage,
 )
 from langchain_core.pydantic_v1 import SecretStr
+from pytest import CaptureFixture, MonkeyPatch
 
 from langchain.chat_models.baichuan import (
+    ChatBaichuan,
     _convert_delta_to_message_chunk,
     _convert_dict_to_message,
     _convert_message_to_dict,
@@ -97,3 +101,49 @@ def test__signature() -> None:
     # https://platform.baichuan-ai.com/docs/api#4
     expected_output = "24a50b2db1648e25a244c67c5ab57d3f"
     assert result == expected_output
+
+
+def test_baichuan_key_masked_when_passed_from_env(
+    monkeypatch: MonkeyPatch, capsys: CaptureFixture
+) -> None:
+    """Test initialization with an API key provided via an env variable"""
+    monkeypatch.setenv("BAICHUAN_API_KEY", "test-api-key")
+    monkeypatch.setenv("BAICHUAN_SECRET_KEY", "test-secret-key")
+
+    chat = ChatBaichuan()
+    print(chat.baichuan_api_key, end="")
+    captured = capsys.readouterr()
+    assert captured.out == "**********"
+
+    print(chat.baichuan_secret_key, end="")
+    captured = capsys.readouterr()
+    assert captured.out == "**********"
+
+
+def test_baichuan_key_masked_when_passed_via_constructor(
+    capsys: CaptureFixture,
+) -> None:
+    """Test initialization with an API key provided via the initializer"""
+    chat = ChatBaichuan(
+        baichuan_api_key="test-api-key", baichuan_secret_key="test-secret-key"
+    )
+    print(chat.baichuan_api_key, end="")
+    captured = capsys.readouterr()
+    assert captured.out == "**********"
+
+    print(chat.baichuan_secret_key, end="")
+    captured = capsys.readouterr()
+
+    assert captured.out == "**********"
+
+
+def test_uses_actual_secret_value_from_secret_str() -> None:
+    """Test that actual secret is retrieved using `.get_secret_value()`."""
+    chat = ChatBaichuan(
+        baichuan_api_key="test-api-key", baichuan_secret_key="test-secret-key"
+    )
+    assert cast(SecretStr, chat.baichuan_api_key).get_secret_value() == "test-api-key"
+    assert (
+        cast(SecretStr, chat.baichuan_secret_key).get_secret_value()
+        == "test-secret-key"
+    )