diff --git a/en/application-dev/device/usb-guidelines.md b/en/application-dev/device/usb-guidelines.md
index c4f5131536a1f0b55ae973bdf7cdf04d2b8f0980..68c8c3de013e75d56854bf0cf0e3a71aca9eb261 100644
--- a/en/application-dev/device/usb-guidelines.md
+++ b/en/application-dev/device/usb-guidelines.md
@@ -130,8 +130,6 @@ You can set a USB device as the USB host to connect to other USB devices for dat
     usb.bulkTransfer(pipe, inEndpoint, dataUint8Array, 15000).then(dataLength => {
     if (dataLength >= 0) {
       console.info("usb readData result Length : " + dataLength);
-      let resultStr = this.ab2str(dataUint8Array); // Convert uint8 data into a string.
-      console.info("usb readData buffer : " + resultStr);
     } else {
       console.info("usb readData failed : " + dataLength);
     }