TIG arc additive manufacturing was carried out by using 5356-aluminum alloy on AA6061-aluminum alloy substrate. And the effect of welding current and preheat temperature on additive manufacturing were researched. The microstructure was analyzed and the sample tensile strength was tested. The results showed that the heat input has a great influence on the additive manufacturing forming of aluminum alloy. The fusion width is used as index of heat input to adjust the current accordingly to realize additive manufacturing forming of the aluminum alloy. The deposition is well bonded to substrate. The columnar dendrite is formed between the bonding zone and layer boundary zone. The equiaxed grain is formed inside a layer. The top layer presents a trend of equiaxed grain transformation of fine dendrite due to its good heat dissipation environment. The hardness distribution of the deposited layer is homogeneity with an average hardness of 71.3 HV. The yield strength of deposited layer is 112 MPa

the tensile strength is 255 MPa and the elongation is 28.3%

the tensile fracture is ductile fracture.