An upconversion luminescence agent Er3+:Y3Al5O12 mixed with the ZnO that utilizing visible light was synthesized by using sol-gel method and the hydrothermal method，and it was charactered by XRD and SEM. Based on the methyl orange, the photocatalytic activity of the Er3+:Y3Al5O12 mixed with the ZnO was researched under the visible light irradiation. In addition, the influence of the calcine temperature、calcine time、the visible light irradiation time and intensity、the dye initial concentration and the amount of catalyst on the degradation rate of the methyl orange were investigated. The results revealed that the degradation rate increased significantly by adding upconversion luminescence agent Er3+:Y3Al5O12 , and the degradation rate was the best when the 10% of the amount of catalyst .
