diff --git a/AssetManager.Infrastructure/Services/MarketDataService.cs b/AssetManager.Infrastructure/Services/MarketDataService.cs
index 0311547..3b155de 100644
--- a/AssetManager.Infrastructure/Services/MarketDataService.cs
+++ b/AssetManager.Infrastructure/Services/MarketDataService.cs
@@ -428,12 +428,20 @@ public class MarketDataService : IMarketDataService
     /// </summary>
     private DateTime GetCacheExpirationTime(string assetType)
     {
-        return assetType.ToLower() switch
+        if (assetType.Equals("crypto", StringComparison.OrdinalIgnoreCase))
         {
-            "stock" => DateTime.Now.AddMinutes(15), // 股票缓存15分钟
-            "crypto" => DateTime.Now.AddMinutes(1), // 加密货币缓存1分钟
-            _ => DateTime.Now.AddMinutes(15)
-        };
+            return DateTime.Now.AddMinutes(1); // 加密货币7*24小时交易，缓存1分钟
+        }
+
+        // 美股交易时段：9:30-16:00 美国东部时间 = 14:30-21:00 UTC（夏令时）/15:30-22:00 UTC（冬令时）
+        // 简化处理：UTC时间14:00-22:00视为美股交易时段
+        var nowUtc = DateTime.UtcNow;
+        if (nowUtc.Hour >= 14 && nowUtc.Hour < 22 && nowUtc.DayOfWeek is not DayOfWeek.Saturday and not DayOfWeek.Sunday)
+        {
+            return DateTime.Now.AddMinutes(15); // 交易时段缓存15分钟
+        }
+        
+        return DateTime.Now.AddHours(24); // 非交易时段（盘前/盘后/周末）缓存24小时，节省API调用
     }
 }