diff --git a/AssetManager.Infrastructure/Services/ExchangeRateService.cs b/AssetManager.Infrastructure/Services/ExchangeRateService.cs
index 6134ca8..80d7f61 100644
--- a/AssetManager.Infrastructure/Services/ExchangeRateService.cs
+++ b/AssetManager.Infrastructure/Services/ExchangeRateService.cs
@@ -50,17 +50,17 @@ public class ExchangeRateService : IExchangeRateService
 
         try
         {
-            // 以USD为基础货币获取所有汇率
-            var response = await _httpClient.GetFromJsonAsync<ExchangeRateResponse>($"https://v6.exchangerate-api.com/v6/4a8a42b4b9a3c4d5e6f7a8b9/latest/{BaseCurrency}");
+            // 使用免费的开放汇率接口，无需API key
+            var response = await _httpClient.GetFromJsonAsync<OpenExchangeRateResponse>($"https://open.er-api.com/v6/latest/{BaseCurrency}");
             
-            if (response == null || response.ConversionRates == null || response.Result != "success")
+            if (response == null || response.Rates == null || response.Result != "success")
             {
                 _logger.LogError("汇率API调用失败: {Message}", response?.ErrorType ?? "未知错误");
                 throw new Exception("汇率服务暂时不可用");
             }
 
             // 转换为USD -> 目标币种的汇率字典
-            var usdRates = response.ConversionRates;
+            var usdRates = response.Rates;
 
             // 计算 from -> to 的汇率：(1 from = x USD) * (1 USD = y to) = x*y to
             decimal fromToUsd = 1 / usdRates[fromCurrency.ToUpper()];
@@ -125,7 +125,7 @@ public class ExchangeRateService : IExchangeRateService
 }
 
 /// <summary>
-/// 汇率API响应模型
+/// 汇率API响应模型（exchangerate-api.com）
 /// </summary>
 public class ExchangeRateResponse
 {
@@ -133,3 +133,13 @@ public class ExchangeRateResponse
     public string ErrorType { get; set; } = string.Empty;
     public Dictionary<string, decimal> ConversionRates { get; set; } = new();
 }
+
+/// <summary>
+/// 开放汇率API响应模型（er-api.com）
+/// </summary>
+public class OpenExchangeRateResponse
+{
+    public string Result { get; set; } = string.Empty;
+    public string ErrorType { get; set; } = string.Empty;
+    public Dictionary<string, decimal> Rates { get; set; } = new();
+}