Laser welding is an efficient and precise welding method using high energy density laser beam as a heat source. Laser welding is one of the important applications of laser material processing technology. It mainly used for welding thin wall material and low speed in the 1970 s. The welding process is thermal conduction, i.e. the laser radiation heating surface, the surface heat to the internal diffusion through heat conduction, by controlling the width of laser pulse, energy, peak power and repeating frequency, parameters such as melting of components, to form specific molten pool. Because of its unique advantages, it has been successfully used in precision welding of micro and small parts.