The technical characteristic and the effect of technical parameters on welding formation and the solidification characteristic of weld are discussed in detail by Al-alloy 2219 with unequal thickness VPPA vertical welding experiments. The comprehensive properties of the joint are assessed and the optimal welding process of the joint is obtained. The test results show that the good matching of VPPA parameters is the key to obtain stable arc keyhole and weld shaping. And its weld has no porosity and inclusion. The outstanding mechanical properties and joint quality exceed the weld quality by traditional TIG.