Corrosion of steel bar caused by chloride invasion is one of the common diseases of concrete structure, so the ability of concrete to resist chloride invasion has an important influence on its durability. Chloride ion erosion test is an effective means to study the law of chloride ion invasion, but most of the current research results are aimed at ordinary concrete without stress, and there are few studies on concrete under stress. In order to study the chloride invasion resistance of concrete under stress, the concrete was soaked in salt solution and salt spray test. The test results of uncracked specimens under different water-cement ratio, stress state, stress level and working environment were obtained, and the results were compared and analyzed. The test results show that reducing the water-cement ratio can improve the chloride ion erosion resistance of concrete. The content of chloride ion in tensile stress state is higher than that in non-stress state. The content of chloride ion under compressive stress depends on the level of compressive stress. The effect of salt soaking environment on concrete structure is much more serious than that of salt spray.