The laser welding is one kind take the high energy density laser beam as the heat source highly effective, the accurate welding method. The laser welding has the power density heat source to be big, the welded joint depth width ratio is big, the line energy is low, after the welding distorts slightly and so on the characteristics. The welding, the flash heat and the cooling rate may avoid the weld joint the structure which different creates as a result of the welding process in physico-chemical properties being non-uniform.