diff --git a/app/core/config.py b/app/core/config.py
index 41a37daf..5948f50a 100644
--- a/app/core/config.py
+++ b/app/core/config.py
@@ -982,12 +982,35 @@ class Settings(BaseSettings, ConfigModel, LogConfigModel):
         )
 
     @property
-    def PROXY(self):
+    def PROXY(self) -> Optional[Dict[str, str]]:
+        """
+        获取 requests 兼容的系统代理配置。
+        """
         if self.PROXY_HOST and self.PROXY_HOST.strip():
+            proxy_host = self.PROXY_HOST.strip()
             return {
-                "http": self.PROXY_HOST,
-                "https": self.PROXY_HOST,
+                "http": proxy_host,
+                "https": proxy_host,
             }
+        https_proxy = self._get_env_proxy("HTTPS_PROXY", "https_proxy")
+        http_proxy = self._get_env_proxy("HTTP_PROXY", "http_proxy")
+        proxy_host = https_proxy or http_proxy
+        if proxy_host:
+            return {
+                "http": http_proxy or proxy_host,
+                "https": https_proxy or proxy_host,
+            }
+        return None
+
+    @staticmethod
+    def _get_env_proxy(*names: str) -> Optional[str]:
+        """
+        按顺序读取非空代理环境变量。
+        """
+        for name in names:
+            proxy_host = os.environ.get(name)
+            if proxy_host and proxy_host.strip():
+                return proxy_host.strip()
         return None
 
     @property
diff --git a/tests/test_proxy_config.py b/tests/test_proxy_config.py
new file mode 100644
index 00000000..eb3ca923
--- /dev/null
+++ b/tests/test_proxy_config.py
@@ -0,0 +1,75 @@
+from app.core.config import Settings
+
+
+PROXY_ENV_NAMES = (
+    "PROXY_HOST",
+    "HTTP_PROXY",
+    "HTTPS_PROXY",
+    "http_proxy",
+    "https_proxy",
+)
+
+
+def clear_proxy_env(monkeypatch) -> None:
+    """
+    清理测试进程中的代理环境变量。
+    """
+    for name in PROXY_ENV_NAMES:
+        monkeypatch.delenv(name, raising=False)
+
+
+def test_proxy_prefers_proxy_host_over_standard_env(monkeypatch) -> None:
+    """
+    PROXY_HOST 应优先于标准代理环境变量。
+    """
+    clear_proxy_env(monkeypatch)
+    monkeypatch.setenv("HTTPS_PROXY", "http://env-proxy.example.com:7890")
+
+    settings = Settings(PROXY_HOST=" http://custom-proxy.example.com:7890 ")
+
+    assert settings.PROXY == {
+        "http": "http://custom-proxy.example.com:7890",
+        "https": "http://custom-proxy.example.com:7890",
+    }
+
+
+def test_proxy_falls_back_to_standard_proxy_env(monkeypatch) -> None:
+    """
+    未配置 PROXY_HOST 时应读取 HTTP_PROXY 和 HTTPS_PROXY。
+    """
+    clear_proxy_env(monkeypatch)
+    monkeypatch.setenv("HTTP_PROXY", "http://http-proxy.example.com:7890")
+    monkeypatch.setenv("HTTPS_PROXY", "http://https-proxy.example.com:7890")
+
+    settings = Settings(PROXY_HOST=None)
+
+    assert settings.PROXY == {
+        "http": "http://http-proxy.example.com:7890",
+        "https": "http://https-proxy.example.com:7890",
+    }
+
+
+def test_proxy_reuses_single_standard_env_for_both_schemes(monkeypatch) -> None:
+    """
+    只配置单个标准代理环境变量时应同时用于 http 和 https。
+    """
+    clear_proxy_env(monkeypatch)
+    monkeypatch.setenv("HTTP_PROXY", "http://http-proxy.example.com:7890")
+
+    settings = Settings(PROXY_HOST=None)
+
+    assert settings.PROXY == {
+        "http": "http://http-proxy.example.com:7890",
+        "https": "http://http-proxy.example.com:7890",
+    }
+
+
+def test_proxy_returns_none_without_any_proxy(monkeypatch) -> None:
+    """
+    未配置任何代理时应返回 None。
+    """
+    clear_proxy_env(monkeypatch)
+
+    settings = Settings(PROXY_HOST=None)
+
+    assert settings.PROXY is None