In order to satisfy the requirements of laser on the output wavelength stability in the methane gas detection, a current driving and temperature control system is designed with taking STM32F103RCT6 as the microprocessor core, including signal generating circuit, filter circuit, and temperature acquisition and control circuit, etc. The signal chip is used to generate sawtooth frequency sweep signal, sine modulated signal and DC bias signal, and all the signals are stacked as laser injection current. At the same time, a secondary cooling system for laser is built to make the laser wavelength scan near the methane gas absorption peak(1 653.72 nm) through the tuning of temperature and current, and thus the gas can be fully absorbed. Experiments show the whole system works stably, and it can work sustainably more than 36 h with temperature error of ±0.008℃,current drive error of 0.09 mA or less and wavelength error in micrometer level, which meets the design requirements.