The self-designed device carried out the mortar fatigue and chloride salt joint action test to explore the chloride ion transport behavior in concrete under fatigue load. The specific crack area was used to characterize the damage of the specimen and analyze the mortar damage and chloride ion transport performance under different fatigue load levels. The correlation between mortar damage and chloride ion transport was disscussed. The results indicated that when the upper limit of fatigue is less than 0.4 times the strength of the specimen, the chloride diffusion coefficient increases slowly. When the upper limit of fatigue is greater than 0.4 times the strength of the specimen, the growth of chloride diffusion coefficient accelerates. The mortar damage increases with the increase of fatigue load level.