Human survival and social development have been seriously affected by water pollution.In order to solve this problem,photocatalysts are used to treat pollutants in water.A hydrothermal method was chosen to prepare a new photocatalyst used graphite-phase carbon nitride(g-C3N4)as a carrier,doped with a small amount of ZnSnO3 to reduce the contaminant content in water,and the optimum conditions for the preparation of this catalyst were investigated.The photocatalytic activity of ZnSnO3/g-C3N4 catalyst was found to be the best when the amount of doping was 10%,the reaction temperature was controlled at 150℃ and the reaction time was 4 hours.When 80 mg of the catalyst was added to 10 mg/L rhodamine B solution,the degradation rate of rhodamine B reached 83.61%when the photocatalytic reaction time was 100 min.The morphological and composition characteristics of ZnSnO3/g-C3N4catalyst were detected by scanning electron microscopy(SEM),transmission electron microscopy(TEM),X-ray diffraction(XRD)and BET.