A novel frequency stabilization method is achieved. The variation of frequency is obtained by detecting saturated absorption signal, and the system is composed of a temperature coarse adjustment and a current fine adjustment to keep the frequency stabilization of the diode laser. The hardware and the software of the frequency stabilization system based on micro control unit are outlined. Through the experimental test, it can automatically achieve frequency stabilization after power on, and can work continuously and stably in more than 180 days. The initial stability of the laser is 4.57×10-11 (1 s),3×10-12 (1024 s), 2.78×10-12 (8192 s) . It provides a method to realize the miniaturization and modularity of frequency stability diode laser.