In recent years, laser machine has been widely applied in the military realm. However, the driving power supply is the most important factor that limits the whole performance of the laser machine. According to the request of the great power laser to the drive supply, a new design based on constant current power source is proposed, which includes a RLC quasi-resonant converter technique and a topologic structure of the whole bridge. To achieve the effective protection of laser, a constant current source driver, soft start - up, limit flow and limit electric voltage implement are taken. And, the electric circuit of temperature control is adopted to control the temperature of the laser, which can ensure the stability of output power. In addition, principle figures of the filter circuit, main power supply circuit and protection circuit are included. Finally, the high stability and the strong interference ability of the newly designed power supply are verified through experiments.