The watershed non-point pollution model AnnAGNPS and water quality model CE-QUAL-W2wereintegrated to apply.Outputting the non-point source pollution loads based on AnnAGNPS model and converting the loads as the inputs of CE-QUAL-W2model,this paper attempts to predict the water quality of Jinpen reservoir and study the impacts of the non-point source pollutions on water quality.Results show that: （1）non-point source pollutions have greater impacts on water quality of Jinpen reservoir in the flood periodthan in the non-flood period;（2）the impacts of non-point source pollutions on water quality make a greatdifference between longitudinal and vertical water qualities;（3）forests play a significant role in the reductionof non-point source pollution in the watershed;（4）when predicting the water quality of reservoir,non-pointsource pollutions should be treated differently in the flood and non-flood period.