Recently the problems of resistance spot welding (RSW) stainless steel railway vehicles are causing more attention for poor surface quality. Lap laser welding of stainless steel is investigated with OED(Orthogonal experimental designing ) in this study to replace RSW with the aim of to increase the aesthetics of the car body by eliminating visible indentation on the surface and the flatness of the skin reducing welding deformations. After welding tensile tests and microstructure analysis are performed. The optimization of process parameters were: laser power =2.5kW；welding speed=2.2m/min, focal position=0mm. The fusion zone is symmetrical about the axis of the laser beam and no welding cracks or porosity can be found in any of the welds. This work has great significance of improving the manufacturing level of stainless steel railway vehicles.