Abstract: The resistance projection welding process was modeled in this work. The element of plane 223 was adopted to simulate thermal-electric-mechanical coupled projection welding simultaneously. The simulation result was compared with that of the experiment. The nugget size showed good agreement between simulation and experiment which vertified the model. The simulation result showed that the maximum von-mises stress and strain located around the projection and exceeds the yield stress of aluminum,forming a plastic strain zone. At welding period, the maximum temperature located in the faying interface between projection and seal cover. Along with the temperature rising, the projection collapsed rapidly and the nugget was formed in the later stage of welding period. The final depth of fusion was 1.42 mm. The direct molding of resistance projection welding provide a good reference for optimize the technology parameters.