diff --git a/lib/helper/coverage.js b/lib/helper/coverage.js
index 32ae710..05514cc 100644
--- a/lib/helper/coverage.js
+++ b/lib/helper/coverage.js
@@ -26,29 +26,50 @@ module.exports = wd => {
    * @type utility
    * @return {Promise.<boolean>}
    */
-  wd.addPromiseChainMethod('coverage', function() {
+  wd.addPromiseChainMethod('coverage', function(opts = {}) {
+    let {
+      coverageIgnore = program.coverageIgnore,
+      keys,
+    } = opts;
     const tempDir = path.join(cwd, 'coverage', '.temp');
     _.mkdir(tempDir);
-    return this.execute('return window.__coverage__')
-      .then(__coverage__ => {
-        if (!__coverage__) {
-          return this.execute('return location.href').then(url => {
-            logger.info(`>> coverage failed: ${url}`);
+    return this.execute('return { allKeys: Object.keys(window.__coverage__) }')
+      .then(async res => {
+        const { allKeys } = res;
+        if (!keys) {
+          keys = allKeys;
+        }
+        if (coverageIgnore) {
+          logger.info('handle coverageIgnore');
+          const ignoreReg = new RegExp(coverageIgnore, 'i');
+          keys = keys.filter(k => {
+            return !ignoreReg.test(k);
           });
         }
-        const file = path.join(tempDir, `${+new Date()}_coverage.json`);
-        if (program.coverageIgnore) {
-          const ignoreReg = new RegExp(program.coverageIgnore, 'i');
-          for (const k in __coverage__) {
-            if (ignoreReg.test(k)) {
-              delete __coverage__[k];
+        if (!keys.length) {
+          logger.info('coverage keys is empty');
+          return;
+        }
+        const covFile = path.join(tempDir, `${+new Date()}_coverage.json`);
+        const writer = fs.createWriteStream(covFile);
+        writer.write('{');
+        for (let i = 0; i < keys.length; i++) {
+          const coverage = await this.execute(`return window.__coverage__['${keys[i]}']`);
+          if (coverage) {
+            const coverageJSON = JSON.stringify(coverage);
+            writer.write(`"${keys[i]}":${coverageJSON}`);
+            if (i < keys.length - 1) {
+              writer.write(',');
             }
           }
         }
-        fs.writeFileSync(file, JSON.stringify(__coverage__, null, 2));
-      })
-      .catch(e => {
-        console.log(e);
+        writer.write('}');
+        await new Promise(resolve => {
+          writer.end(() => {
+            writer.close();
+            resolve();
+          });
+        });
       });
   });
 };
diff --git a/package.json b/package.json
index 5898881..2efae5a 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "macaca-wd",
-  "version": "4.3.4",
+  "version": "4.3.5",
   "description": "Macaca webdirver API for Node.js",
   "keywords": [
     "macaca",