Abstract: In order to prevent high concentration of CO and gas explosion caused by spontaneous combustion of coal during drilling for coal seam gas drainage, the paper proposed a design scheme of mine-used safety protection device for preventing fire during drilling. The device monitors concentration of CO and gas by sensors, and uses single-chip microcompute to achieve automatic switching of high-pressure air and pressure water. Field tests show that the device can realize automatic switching of high-pressure air and pressure water and crush out burning coal when spontaneous combustion occurs during drilling.