Abstract: In this paper, it was studied that the effects of combination mode, plate thickness and heat treatment of joints on mechanical properties of joints by using Q235 steel sheet and 5083 aluminum sheet. The experimental results showed that the performance of the joint was better when the 5083 aluminum sheet was used as the lower plate, and the thickness of Q235 upper plate had a certain effect on the optimization for the performance of the joint. In this experiment, the combination mode of joint b# was the best process parameter, which was 1.5mm Q235-2.0 mm 5083.After being baked, the joint was neutral, and its failure load and displacement increased in varying degrees. For example, the failure load of joint b# increased by 5.80 %, and 8.26 % for its failure displacement. During the process of automobile body painting, the mechanical properties and stability of the joint could be optimized to a certain extent by being baked, which would not result in the loss of strength of the joint.