Abstract: Roadway tunneling technology and equipment level has a direct economic impact on coal mining. Shield tunneling machine is a kind of large engineering machinery special for full section excavation of tunnel engineering. Compared with the traditional construction machinery,it can remarkably improve the production efficiency and safety. In view of the present situation that the shield tunneling machine is introduced in low gas coal mine for excavation roadway,we design and implement a protector for shield tunneling machine. We introduce hardware and software design of the system in detail. The protector of the device adopts distributed control,which can carry out real-time exchange data through 485 or CAN bus. The implementation of real-time monitoring, sound and light alarm, fault detection and function extension for harmful gas concentration and other parameters around the shield tunneling machine provides a solution for shield tunneling in the process of roadway tunneling.