Abstract: A portable laser methane detection and alarm device for mine is designed. It uses tunable diode laser absorption spectroscopy（TDLAS） technology to realize the laser signal acquisition, analysis, storage with the STM32 master control chip, and sends the data to the substation with the ZigBee wireless technology at the same time, which improves the detection accuracy and reliability of the methane portable instrument. The monitor can monitor the walking trajectory and gas condition of the inspector on the ground in real time.