diff --git a/src/SKIT.FlurlHttpClient.Wechat.Work/Extensions/WechatWorkClientExecuteCgibinExternalContactExtensions.cs b/src/SKIT.FlurlHttpClient.Wechat.Work/Extensions/WechatWorkClientExecuteCgibinExternalContactExtensions.cs
index 499425a8..f4d0642e 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.Work/Extensions/WechatWorkClientExecuteCgibinExternalContactExtensions.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.Work/Extensions/WechatWorkClientExecuteCgibinExternalContactExtensions.cs
@@ -283,6 +283,26 @@ namespace SKIT.FlurlHttpClient.Wechat.Work
             return await client.SendRequestWithJsonAsync<Models.CgibinExternalContactOpenGroupIdToChatIdResponse>(flurlReq, data: request, cancellationToken: cancellationToken);
         }
 
+        /// <summary>
+        /// <para>异步调用 [POST] /cgi-bin/externalcontact/to_service_external_userid 接口。</para>
+        /// <para>REF: https://open.work.weixin.qq.com/api/doc/90001/90143/95195 </para>
+        /// </summary>
+        /// <param name="client"></param>
+        /// <param name="request"></param>
+        /// <param name="cancellationToken"></param>
+        /// <returns></returns>
+        public static async Task<Models.CgibinExternalContactToServiceExternalUserIdResponse> ExecuteCgibinExternalContactToServiceExternalUserIdAsync(this WechatWorkClient client, Models.CgibinExternalContactToServiceExternalUserIdRequest request, CancellationToken cancellationToken = default)
+        {
+            if (client is null) throw new ArgumentNullException(nameof(client));
+            if (request is null) throw new ArgumentNullException(nameof(request));
+
+            IFlurlRequest flurlReq = client
+                .CreateRequest(request, HttpMethod.Post, "cgi-bin", "externalcontact", "to_service_external_userid")
+                .SetQueryParam("access_token", request.AccessToken);
+
+            return await client.SendRequestWithJsonAsync<Models.CgibinExternalContactToServiceExternalUserIdResponse>(flurlReq, data: request, cancellationToken: cancellationToken);
+        }
+
         #region ContactWay
         /// <summary>
         /// <para>异步调用 [POST] /cgi-bin/externalcontact/add_contact_way 接口。</para>
diff --git a/src/SKIT.FlurlHttpClient.Wechat.Work/Models/CgibinExternalContact/CgibinExternalContactToServiceExternalUserIdRequest.cs b/src/SKIT.FlurlHttpClient.Wechat.Work/Models/CgibinExternalContact/CgibinExternalContactToServiceExternalUserIdRequest.cs
new file mode 100644
index 00000000..73ed63e3
--- /dev/null
+++ b/src/SKIT.FlurlHttpClient.Wechat.Work/Models/CgibinExternalContact/CgibinExternalContactToServiceExternalUserIdRequest.cs
@@ -0,0 +1,15 @@
+namespace SKIT.FlurlHttpClient.Wechat.Work.Models
+{
+    /// <summary>
+    /// <para>表示 [POST] /cgi-bin/externalcontact/to_service_external_userid 接口的请求。</para>
+    /// </summary>
+    public class CgibinExternalContactToServiceExternalUserIdRequest : WechatWorkRequest
+    {
+        /// <summary>
+        /// 获取或设置代开发自建应用的外部联系人账号。
+        /// </summary>
+        [Newtonsoft.Json.JsonProperty("external_userid")]
+        [System.Text.Json.Serialization.JsonPropertyName("external_userid")]
+        public string ExternalUserId { get; set; } = string.Empty;
+    }
+}
diff --git a/src/SKIT.FlurlHttpClient.Wechat.Work/Models/CgibinExternalContact/CgibinExternalContactToServiceExternalUserIdResponse.cs b/src/SKIT.FlurlHttpClient.Wechat.Work/Models/CgibinExternalContact/CgibinExternalContactToServiceExternalUserIdResponse.cs
new file mode 100644
index 00000000..2b430b35
--- /dev/null
+++ b/src/SKIT.FlurlHttpClient.Wechat.Work/Models/CgibinExternalContact/CgibinExternalContactToServiceExternalUserIdResponse.cs
@@ -0,0 +1,15 @@
+namespace SKIT.FlurlHttpClient.Wechat.Work.Models
+{
+    /// <summary>
+    /// <para>表示 [POST] /cgi-bin/externalcontact/to_service_external_userid 接口的响应。</para>
+    /// </summary>
+    public class CgibinExternalContactToServiceExternalUserIdResponse : WechatWorkResponse
+    {
+        /// <summary>
+        /// 获取或设置第三方应用的外部联系人账号。
+        /// </summary>
+        [Newtonsoft.Json.JsonProperty("external_userid")]
+        [System.Text.Json.Serialization.JsonPropertyName("external_userid")]
+        public string ExternalUserId { get; set; } = default!;
+    }
+}
diff --git a/test/SKIT.FlurlHttpClient.Wechat.Work.UnitTests/ModelSamples/CgibinExternalContact/CgibinExternalContactToServiceExternalUserIdRequest.json b/test/SKIT.FlurlHttpClient.Wechat.Work.UnitTests/ModelSamples/CgibinExternalContact/CgibinExternalContactToServiceExternalUserIdRequest.json
new file mode 100644
index 00000000..c4adf86c
--- /dev/null
+++ b/test/SKIT.FlurlHttpClient.Wechat.Work.UnitTests/ModelSamples/CgibinExternalContact/CgibinExternalContactToServiceExternalUserIdRequest.json
@@ -0,0 +1,3 @@
+{
+    "external_userid": "wmAAAAAAA"
+}
\ No newline at end of file
diff --git a/test/SKIT.FlurlHttpClient.Wechat.Work.UnitTests/ModelSamples/CgibinExternalContact/CgibinExternalContactToServiceExternalUserIdResponse.json b/test/SKIT.FlurlHttpClient.Wechat.Work.UnitTests/ModelSamples/CgibinExternalContact/CgibinExternalContactToServiceExternalUserIdResponse.json
new file mode 100644
index 00000000..f1688c16
--- /dev/null
+++ b/test/SKIT.FlurlHttpClient.Wechat.Work.UnitTests/ModelSamples/CgibinExternalContact/CgibinExternalContactToServiceExternalUserIdResponse.json
@@ -0,0 +1,5 @@
+{
+    "errcode": 0,
+    "errmsg": "ok",
+    "external_userid": "ooAAAAAAAAAAA"
+}
\ No newline at end of file