Abstract: Recent years, the stainless steel car body has been favored by more users with its unique advantages. The seam welding technology application of stainless steel car body is more and more widely. According to structural characteristics of side roof plate and corrugated plate of the car body , the technical difficulties were analyzed during the seam welding process. The craft equipment and special spreader of side roof plate on seam welding were designed. The reasonable welding process parameters were formulated, and according to the structure characteristics of the seam welding equipment, the reasonable welding sequence of side top plate and corrugated plate were determined. In the end, the weld quality of the corrugated board of stainless steel car body is guaranteed to meet the requirements.