The process of welding foreign aluminum alloy material AMГ-3M(0.5 mm)and domestic aluminum alloy material 3A21/2A12(<0.8 mm) by improved small condenser spot welder was further studied and tested. The parameters of welding process were confirmed, the methods of welding process control were acquired, as well as various means of process tests were put forward. The results tests show that the small condenser spot welder can be used to weld the aluminum alloy sheets in stead of large DC spot welding machines, with feasible welding process and low costs.