diff --git a/edc-web/app/static/js/test_op.js b/edc-web/app/static/js/test_op.js
index 6001a91..04a2d6d 100644
--- a/edc-web/app/static/js/test_op.js
+++ b/edc-web/app/static/js/test_op.js
@@ -8,6 +8,7 @@ let autoRemaining = 0;
 let autoStartTime = "";
 let localSinceStr = "";
 let currentTestMode = null;  // 0=灵敏度, 1=波动, null=未加载
+let currentDeviceState = null;  // 当前设备状态 (0=离线 1=在线 2=通信不良  null=未加载)
 
 let pollInterval = null;
 let nextCmdTimer = null;     // 间隔等待定时器
@@ -18,9 +19,22 @@ let cmdSentAt = 0;           // 最近一次发送 0xB0 时间
 let intervalMs = 10000;      // 默认 10s
 let timeoutMs = 5000;        // 默认 5s
 
+// ─── 设备在线检查 ──────────────────────────────
+
+function checkDeviceOnline() {
+    if (currentDeviceState !== 1) {
+        const stateName = currentDeviceState === 2 ? '通信不良' :
+                          currentDeviceState === 0 ? '离线' : '未知';
+        alert(`设备当前状态为「${stateName}」，无法发送指令`);
+        return false;
+    }
+    return true;
+}
+
 // ─── 手动指令 ─────────────────────────────────
 
 async function sendCmd(cmd) {
+    if (!checkDeviceOnline()) return;
     try {
         const resp = await fetch("/api/command", {
             method: "POST",
@@ -47,6 +61,7 @@ async function toggleAuto() {
 }
 
 async function startAuto() {
+    if (!checkDeviceOnline()) return;
     const count = parseInt(document.getElementById("test-count").value) || 10;
     if (count < 1) return;
 
@@ -309,6 +324,7 @@ async function refreshDeviceStatus() {
         const resp = await fetch(`/api/devices/${DNT_ID}/status`);
         const data = await resp.json();
         if (data.ok) {
+            currentDeviceState = data.state;
             const el = document.getElementById("device-status-text");
             if (el) {
                 el.textContent = data.state_name;