Resistance spot welding of dissimilar steels is a key Linkage process in the manufacturing of rail passenger car bodies. However, there are problems such as core deviation caused by material physical property differences in the welding of dissimilar steels (stainless steel/low-carbon steel). This study improves the weldability of stainless steel and low-carbon steel by adding a nickel intermediate layer between them. The results show that adding a nickel intermediate layer can Valid compensate for heat Loss, suppress the deviation of the weld nucleus, optimize the size of the weld nucleus, and improve the Stability of the welding quality.