Abstract: Taking coal gangue as the research object, this paper investigated the inhibitory effect of two synergistic oxidation inhibitors on the oxidation of Fe²⁺ in coal gangue hill through experiments. Scanning electron microscope (SEM) was used to observe the morphology of the cell and the inhibition mechanism was preliminarily discussed. The results show that when the two oxidation inhibitors are used together, they have an obvious synergistic inhibitory effect on the oxidation of Fe²⁺ in coal gangue. When benzalammonium chloride with the mass concentration of 3 mg/L and glutaraldehyde with the volume fraction of 0.08% are mixed in coal gangue in a volume ratio of 1∶1, the oxidation rate of Fe²⁺ can be lower than 14%.