Abstract: Based on the use requirements of aluminum and stainless steel composite transition joint, analysis on mechanical properties at room temperature, mechanical properties from welding simulation, micro metallography and air tightness of the aluminum and stainless steel transition joints of different material combinations and by different explosion technologies was carried out. It′s found that the temperature can affect the mechanical properties and the tightness of the joints, and that the main positions of the leakage are on the aluminum-aluminum interface and the aluminum-titanium interface. The results provide a research direction for the air tightness of the joint.