Abstract: Two kinds of welding rod, A302 and ENiCrFe-3, were used separately to weld 0Cr18Ni9 steel and 20G steel forming dissimilar welded joints. Behaviors of resistance to hydrogen sulfide stress corrosion cracking of the dissimilar welded joints in solutions containing different concentrations of hydrogen sulfide before and after aging were studied by slow strain rate tensile test. The results show that mechanical properties of the dissimilar welded joints decreased with the increasing of aging time , and the mechanical properties of the joints welded with ENiCrFe-3 were better than those of the joints welded with A302. The corrosion sensitiveness of the joints welded by the both welding rods increased remarkably with the increasing of concentration of H2S, and the property of resistance to stress corrosion for joints welded with ENiCrFe-3 was better than that for joints welded with A302. The property of resistance to stress corrosion cracking for joints welded with the both welding rods was significantly improved by aging treatment at 600 ℃ for 56 h, but lowered for a longer aging time over 98 h.