Abstract: In order to grasp the performance deterioration law of coal gangue under the harsh erosion environment such as sulfate, this paper did indoor simulation experiment and selected four kinds of coal gangues from Tai Yuan, Chang Zhi, Yu Lin, Xu Chang as research target. Strength deterioration of coal gangue and evolution of coal gangue-cement ITZ structure under dry-wet cycle in sulfate/water were studied by macro and micro testing. The results show that water and sulfate solution have significant erosion effect on coal gangue. Under the conditions of water immersion and dry-wet, the softening coefficient of the four coal gangues is only between 0.3 and 0.4, which is significantly lower than that of limestones. And under dry-wet cycle in sulfate solution, their strength reduction rate can reach 80%. The dry-wet conditions of water and sulfate solution also have significant deteriorating effects on the interfacial transition zone（ITZ） of coal gangue-cement. These research results can support the application of coal gangue in roadbed fillers and concrete.