The reclaimed utilization of urban wastewater is an indispensable way for solving the crisis of urban water resource. In order to meet the needs of reclaimed water pollution control, the risk assessment model for reclaimed water utilization in basin are established. GIS was employed to derive all the data and evaluate model in order to get spatial variance and distribution of the risk levels on different scales within study area. The evaluation results can supply the pollution control with target areas. Based on the analysis of reclaimed water data of Beiyun river basin, the paper sets up an index system of risk assessment of reclaimed water. In addition, it applies the mathematics theory to making a comprehensive assessment on the utilizing risk of reclaimed water in the research object, which provides a scientific foundation for risk management of reclaimed water in theory and practice.