Abstract: LD10 aluminum alloy is mainly used in domestic aerospace vehicle propellant tank and mostly joined by TIG welding,and pores often appeared during fusion welding of aluminum alloy. This paper conducted TIG welding of 5.5 mm thick LD10 aluminum alloy plates with different welding parameters and calculated the porosity in the joints. The experimental results show that LD10 aluminum alloy joints made by TIG welding were prone to high porosity. The joints produced by double-faced three-pass welding technique had a higher unqualified rate after X-ray detection,but contained fewer micro-pores in the qualified ones. And micro-pores were much more easier to form in robot automatic welding than in manual welding. Porisity of the welds was 3.28%,2.53%,2.28% and 0.9%,respectively. During tensile test,cracks often generated at the pores in joints with high porosity.