To effectively protect drinking water resources,a scientific assessment on site selection of River drinking water resources was carried out.Twenty-eight key factors including law,environmental quality,water resources assurance and environmental risk were selected,and based on analytic hierarchy process(AHP),a mathematical model of assessment system was established.The weight of factors was defined by the method of document data and expert questionnaire,and these weights were synthesized under single criterion.These influence factors were classified and quantized with laws,technical standards and statistical data.According to the calculation of factor scores and weights,the recommendations of site selection can be given.