The naturally occurring pyrite was characterized using scanning electron microscopy(SEM) and energy dispersive spectrometer(EDS) and used as a Fenton-like catalyst to catalyze H2O2 oxidative discoloration of Azo dye.Factors(solution pH,pollutant initial concentration,H2O2 and pyrite dose,and reaction time) affecting the catalytic performance have been investigated.Results showed that about 95% of color removal rate can be achieved at pH 6.4 after 2min of reaction with 26.6mg/LH2O2 and 1g/L pyrite.To get a deeper understanding of the reaction mechanism,the acid oxidation of pyrite surface in water solution was examined.Results demonstrated that the reutilization times of pyrite has a significant effect on the performance of aid reaction,which was clearly indicated by the concentration change of leached ferrous iron,sulfate and variation of solution pH values.High level of ferrous iron and sulfate in solution along with a great decline in solution pH can be detected when raw pyrite was added to the water solution.Therefore,the observed rapid discoloration of Azo dye in this study was mainly attributed to the homogeneous Fenton reaction between dissolved ferrous iron and H2O2.This research revealed that the catalytic rate of Fenton-like reaction can be greatly improved using pyrite as a new kind of catalyst.Pyrite’s utilization as a catalyst contributes to overcome the limitation of traditional Fenton reactions,and expands the application of Fenton-like reaction in wastewater treatment.