diff --git a/backend/app/proxy_client.py b/backend/app/proxy_client.py
index 3904fc3..bf44882 100644
--- a/backend/app/proxy_client.py
+++ b/backend/app/proxy_client.py
@@ -2,16 +2,20 @@
 import logging
 import httpx
 from datetime import datetime, timezone, timedelta
+from typing import Optional
 from airwallex.client import AirwallexClient
 
 logger = logging.getLogger(__name__)
 
 
 class ProxiedAirwallexClient(AirwallexClient):
-    """AirwallexClient that routes requests through an HTTP or SOCKS5 proxy."""
+    """AirwallexClient that routes requests through an HTTP or SOCKS5 proxy.
+    Also supports x-login-as header for connected accounts.
+    """
 
-    def __init__(self, proxy_url: str | None = None, **kwargs):
+    def __init__(self, proxy_url: str | None = None, login_as: str | None = None, **kwargs):
         self._proxy_url = proxy_url
+        self._login_as = login_as
         super().__init__(**kwargs)
         # Replace the default httpx client with a proxied one
         if proxy_url:
@@ -27,26 +31,30 @@ class ProxiedAirwallexClient(AirwallexClient):
             logger.info("Airwallex client initialized without proxy")
 
     def authenticate(self) -> None:
-        """Override authenticate to use proxy for auth requests too."""
+        """Override authenticate to use proxy and x-login-as for auth requests."""
         if self._token and self._token_expiry and datetime.now(timezone.utc) < self._token_expiry:
             return
 
-        logger.info("Authenticating with Airwallex API at %s (proxy: %s)",
-                     self.auth_url, bool(self._proxy_url))
+        logger.info("Authenticating with Airwallex API at %s (proxy: %s, login_as: %s)",
+                     self.auth_url, bool(self._proxy_url), self._login_as or "none")
 
         auth_kwargs: dict = {"timeout": self.request_timeout}
         if self._proxy_url:
             auth_kwargs["proxy"] = self._proxy_url
 
+        auth_headers = {
+            "Content-Type": "application/json",
+            "x-client-id": self.client_id,
+            "x-api-key": self.api_key,
+        }
+        if self._login_as:
+            auth_headers["x-login-as"] = self._login_as
+
         auth_client = httpx.Client(**auth_kwargs)
         try:
             response = auth_client.post(
                 self.auth_url,
-                headers={
-                    "Content-Type": "application/json",
-                    "x-client-id": self.client_id,
-                    "x-api-key": self.api_key,
-                },
+                headers=auth_headers,
                 content="{}",
             )
 
@@ -61,3 +69,11 @@ class ProxiedAirwallexClient(AirwallexClient):
             logger.info("Authentication successful, token expires in 28 minutes")
         finally:
             auth_client.close()
+
+    @property
+    def headers(self):
+        """Add x-login-as to all API request headers."""
+        h = super().headers
+        if self._login_as:
+            h["x-login-as"] = self._login_as
+        return h
diff --git a/backend/app/services/airwallex_service.py b/backend/app/services/airwallex_service.py
index 98694fd..5f2c965 100644
--- a/backend/app/services/airwallex_service.py
+++ b/backend/app/services/airwallex_service.py
@@ -43,13 +43,14 @@ def get_client(db: Session) -> ProxiedAirwallexClient:
 
     client_id = _get_setting(db, "airwallex_client_id")
     api_key = _get_setting(db, "airwallex_api_key")
-    base_url = _get_setting(db, "airwallex_base_url", "https://api.airwallex.com/")
+    base_url = _get_setting(db, "airwallex_base_url", "https://api-demo.airwallex.com/")
+    login_as = _get_setting(db, "airwallex_login_as")
     proxy_url = _build_proxy_url(db)
 
     if not client_id or not api_key:
         raise HTTPException(status_code=400, detail="Airwallex 凭证未配置，请在系统设置中填写 Client ID 和 API Key")
 
-    config_hash = f"{client_id}:{api_key}:{base_url}:{proxy_url}"
+    config_hash = f"{client_id}:{api_key}:{base_url}:{login_as}:{proxy_url}"
     if _client_instance and _client_config_hash == config_hash:
         return _client_instance
 
@@ -60,11 +61,16 @@ def get_client(db: Session) -> ProxiedAirwallexClient:
         except Exception:
             pass
 
+    # auth_url must match base_url domain
+    auth_url = base_url.rstrip("/") + "/api/v1/authentication/login"
+
     _client_instance = ProxiedAirwallexClient(
         proxy_url=proxy_url,
+        login_as=login_as or None,
         client_id=client_id,
         api_key=api_key,
         base_url=base_url,
+        auth_url=auth_url,
     )
     _client_config_hash = config_hash
     return _client_instance
diff --git a/frontend/src/pages/Settings.tsx b/frontend/src/pages/Settings.tsx
index 1908961..1a46c48 100644
--- a/frontend/src/pages/Settings.tsx
+++ b/frontend/src/pages/Settings.tsx
@@ -139,19 +139,27 @@ export default function Settings() {
       <Form form={form} layout="vertical" disabled={loading}>
         <Card title="Airwallex 凭证" style={{ marginBottom: 16 }}>
           <Form.Item
-            label="Client ID"
+            label="Client ID (x-client-id)"
             name="airwallex_client_id"
             rules={[{ required: true, message: '请输入 Client ID' }]}
+            tooltip="平台级 Client ID，通常以 org_ 开头"
           >
-            <Input placeholder="请输入 Client ID" />
+            <Input placeholder="例如: org_xxxxx" />
           </Form.Item>
           <Form.Item
-            label="API Key"
+            label="API Key (x-api-key)"
             name="airwallex_api_key"
             rules={[{ required: true, message: '请输入 API Key' }]}
           >
             <Input.Password placeholder="请输入 API Key" />
           </Form.Item>
+          <Form.Item
+            label="Account ID (x-login-as)"
+            name="airwallex_login_as"
+            tooltip="连接账户 ID，通常以 acct_ 开头。如果不需要代登录可留空"
+          >
+            <Input placeholder="例如: acct_xxxxx（可选）" />
+          </Form.Item>
           <Form.Item label="Base URL" name="airwallex_base_url">
             <Input placeholder="https://api-demo.airwallex.com/" />
           </Form.Item>