Compared with the external cavity semiconductor laser, distributed feedback laser has a higher temperature regulation rate. In order to achieve saturated absorption frequency stabilization, it is necessary to control the laser temperature precisely. In this paper, the temperature control requirements of the saturated absorption frequency stabilization system is analyzed, a precise temperature control system is designed based on MAX1978 chip.The linear optimization of the temperature bridge circuit is realized by using constant current source, and the parameters of the analog PID circuit are quickly adjusted by using genetic algorithm. Finally the temperature control stability of 0.2mK is achieved, which is 1~2 orders of magnitude higher than that of the similar design. It solves the problem of obvious shaking of saturated absorption spectrum and has a broad application prospect.