diff --git a/public/index.html b/public/index.html
index 7c2831e..073d7fa 100644
--- a/public/index.html
+++ b/public/index.html
@@ -460,8 +460,8 @@
                 </div>
               </div>
               <div class="form-group" style="margin-top: 15px;">
-                <label for="latencyTargetInput">Blackbox 探测目标 (在Prometheus中的instance标签值)</label>
-                <input type="text" id="latencyTargetInput" placeholder="例：8.8.8.8">
+                <label for="latencyTargetInput">Blackbox 探测目标 (在Prometheus中的instance_name标签值)</label>
+                <input type="text" id="latencyTargetInput" placeholder="例：China-USA-Latency">
               </div>
               <div class="form-actions" style="margin-top: 25px; display: flex; justify-content: flex-end;">
                 <button class="btn btn-add" id="btnSaveSiteSettings">保存设置</button>
diff --git a/server/prometheus-service.js b/server/prometheus-service.js
index aedcde0..a4132a6 100644
--- a/server/prometheus-service.js
+++ b/server/prometheus-service.js
@@ -805,7 +805,7 @@ module.exports = {
     if (!blackboxUrl || !target) return null;
     try {
       const normalized = blackboxUrl.trim().replace(/\/+$/, '');
-      const params = new URLSearchParams({ query: `probe_duration_seconds{instance="${target}"}` });
+      const params = new URLSearchParams({ query: `probe_duration_seconds{instance_name="${target}"}` });
       const res = await fetch(`${normalized}/api/v1/query?${params.toString()}`);
       if (!res.ok) return null;
       const data = await res.json();