Abstract: The resistance spot welding joint made of 1.2 mm aluminum alloy 5182-H111 in automobile body was studied. The microstructure and mechanical properties of the welded joints were characterized and analyzed by metallographic observation and tensile test. The effects of welding current, welding time and electrode pressure on the mechanical properties of the joint were studied. At the same time, the electrode life of the welded joint under the optimized parameters was tested. The results show that the optimal parameters of resistance spot welding with 1.2 mm thick 5182-H111 are welding current of 21 kA+ welding time of 200 ms+ electrode pressure of 3.5 kN. Under the technological parameters, the maximum load of the welding spot is 2.4 kN, the welding spot nugget size is 4.9 mm, and the service life of CuCrZr electrode is 40 points.