Abstract: For resolving the problems of resistant spot welding of stainless steel railway vehicles' body,such as poor surface quality and bad airtight,the experiment program was designed by the quadratic regression rotation design plan.The mathematical model between the laser welding parameters(laser power,welding speed and defocusing volume) and the response values(joint tensile strength,penetration and weld width) was established based on the response surface methodology(RSM).According to the demand of surface quality and strength of the joint,the model can be used to optimize the laser welding process parameters and prospect shear tensile strength,penetration,weld width of the joint for getting the optimal combination of the appearance and strength of the joint,which improves the surface quality of the stainless steel vehicle body.