Ferric nitrate was used to provide iron source, and Fe?C₃N₄ composite material was prepared by impregnation method. FT?IR was used to characterize and analyze the prepared materials. The results show that Fe doping does not change the skeleton structure of g?C₃N₄ and can increase the photocatalytic performance of g?C₃N₄ materials. Taking orange II as the target pollutant, Fe?C₃N₄ catalyzed the activation of persulfate to degrade azo dyes under visible light. The effects of persulfate dosage, Fe?C₃N₄ dosage, pollutant concentration and pH conditions on the degradation effect were examined, and the reaction kinetics was studied to analyze the stability of the prepared catalytic materials. The results show that when the Fe?C₃N₄ concentration is 2.0 g/L, the molar ratio of persulfate to pollutants is 1 200∶1, and pH=3, the degradation effect is best, and the degradation rate is 77.8%; Fe?C₃N₄/persulfate system is dual the degradation of nitrogen dyes satisfies the quasi?second?order kinetic equation; Fe?C₃N₄ material is reusable.