Laser welding is a high efficient precision welding method which is in the use of high energy density laser beam as a heat source . Laser welding is one of the important aspects of laser processing technology. Laser radiates and heats the workpiece surface, The surface heat diffuses to the inside through heat conduction, Then the laser makes the workpiece melting and form the specific welding pool by controlling the laser pulse width, energy, peak power and repetition frequency. Due to its unique advantages, it has been successfully applied to the precise welding for micro parts and small parts.