In order to analyze the impact of new low toxic organophosphorus insecticide “1% Abate Granules” on river water quality, indoor experiments with different adding concentrations and reaction time were set up. TP, NH₃-N and S^2- were taken as target factors to analyze the concentration of water pollutants after the application of the insecticide. The results showed that in the water samples of different test groups the mass concentration of S^2- was lower than 0. 02 mg/L, the mass concentration of NH₃-N was between 0. 029 mg/L and 0. 036 mg/L, which reached the class I standard of surface water. After 1 h of adding different concentrations of insecticide, ρ(TP)of water has reached a stable state and remained stable within 60 hours. Insecticide dosage and ρ(TP)of water was significantly positive correlation(R2=0. 85). There was no significant difference in TP release between different treatment groups, which ranged from 1. 06 mg/g to 1. 30 mg/g. The recommended appropriate dosage of “1% Abate Granules” will not worsen the river water quality to inferior class V, but increasing the dosage will increase the risk of TP pollution and eutrophication.