Abstract: Tungsten inert gas (TIG) welded joint of 6061/5052 dissimilar aluminum alloys was prepared. The microstructure, grain size, hardness, stress corrosion resistance and pre-corrosion fatigue properties of the joint were studied. The results show that the average grain size of 6061 aluminum alloy base metal, weld and 5052 aluminum alloy base metal was 38.42, 47.13, 41.17 µm, respectively. The microhardness of base metal was higher than that of heat affected zone and weld zone, and the minimum hardness (51 HV) appeared in the heat affected zone on the side of 6061 aluminum alloy. The fracture location of the joint was at the position which was 14 mm away from the weld center on the side of 6061 aluminum alloy after stress corrosing in both NaCl solution and air, and the tensile strength, yield strength, percentage elongation after fracture and corrosion resistance property in NaCl solution were slightly higher than those in air. With the increase of HCl content in NaCl solution, the intergranular corrosion depth of the welded joint increased, the fatigue life was shortened, and the fracture location changed from the weld zone to the 5052 aluminum alloy base metal.