According to the existing water quality monitoring data from monitoring sites in Jining city,the clustering analysis method is employed to analyze and evaluate the water quality of Jining city.First of all,by using the statistical software SPSS,we aggregate and classify these monitoring sites;then,the composite index is applied in evaluating the water quality of these monitoring sites; at last,the water quality of Jining is divided into six categories by the clustering results and the comprehensive evaluation combined together. In the regional water environment evaluation,monitoring sites are classified by using clustering method conforms to the distribution actual of different pollution sources,which avoids the defect caused by only using the comprehensive index method.