Abstract: Based on the principle of infrared detection, MSP430F1611 was taked as the core to design a kind of infrared methane sensor. In order to improve the stability of infrared light and provide circuit over-voltage protection, voltage driving circuit was designed; Through the hardware filter circuit, signal acquisition still contained noise, and then , the signal after the hardware filtering , was filtered digitally using FIR filter; In the laboratory , the sensor was used to test standard methane gas ,and the measurement results show that the precision of the sensor is suitable for methane detection in coal industry.