diff --git a/src/api/player-auth.ts b/src/api/player-auth.ts
index f1a883f..bf5d953 100644
--- a/src/api/player-auth.ts
+++ b/src/api/player-auth.ts
@@ -34,5 +34,9 @@ export function getPlayerAuthCaptcha(): Promise<PlayerAuthCaptchaResponse> {
 
 /** `POST /api/v1/player/auth/login`（公开） */
 export function postPlayerAuthLogin(body: PlayerAuthLoginPayload): Promise<PlayerAuthLoginData> {
-  return lotteryRequest.post<PlayerAuthLoginData>(`/player/auth/login`, body);
+  const siteCode = process.env.NEXT_PUBLIC_PLAYER_SITE_CODE?.trim();
+  return lotteryRequest.post<PlayerAuthLoginData>(`/player/auth/login`, {
+    ...(siteCode ? { site_code: siteCode } : {}),
+    ...body,
+  });
 }