With TiO2 - P25 as photocatalyst, endocrine disruptors prometryn as model of pollutants, H2O2 was studied to help TiO2 visible light catalytic degradation reaction characteristics of prometryn. Suggest that H2O2 can help TiO2 visible light catalytic degradation of prometryn, reaction 120 min, prometryn degradation rate was 80%; Reaction process, the control system solution pH value of 3.0 or so, the initial concentration ratio of H2O2 with prometryn about 45:1 relatively appropriate; In the process of the degradation of prometryn, methyl, sulfonium and amine oxide removal, NO3 -, SO42 - was released continuously, the TOC removal rate was 70%, and the degradation of end product for cyanuric acid; Through the spectrum analysis of the reaction system, according to structure, forming complexes adsorbed on the surface of TiO2 H2O2 under visible light is converted to free radical active species, such as the degradation of prometryn involves the generation of hydroxyl radical (· OH) and participation.