Abstract: Picosecond pulse light source is the core device of a quantum key distribution system. In order to realize the localization of picosecond pulse light source, a gigahertz picosecond pulse laser module was developed based on domestic chips. The module was fabricated by using proportion integration division algorithm to control the temperature so that the wavelength drifts within 0.01nm. The external positive intrinsic negative tube was used to detect the light power, and the driving current of the laser diode was adjusted by feedback. In the meantime, experiments were carried out to verify the theoretical results. The results show that the constant current source and short pulse circuit are controlled accurately by domestic microcontroller to drive the laser diode. The output light pulse frequency can reach 1.25GHz, and the pulse width is about 50ps. When the optical power is -3dB, the spectral width is less than 0.2nm, and the output light wavelength and power is stable. The picosecond pulse laser module of localization can meet the requirements of quantum key distribution system for light source stability.