Abstract: A study on 2219 aluminum alloy welding using high frequency energy coupling pulsed TIG welding process are carried out. It shows that using a special AC with the high-frequency pulse current can refine the microstructure of weld, eliminate pores and reduce cracks and other defects effectively, and also can improve the properties of the aluminum alloy joint significantly. The properties of single-layer joint and double-layer joint were investigated and compared by means of quantitative analysis of grain size. The paper proposed a way to reach "controllable joint property" by thermal cycles controlling, which makes the joint microstructure more homogeneous. It is a new way to improve the comprehensive mechanical properties of joint and therefore has applicability in engineering.