The river water environment bearing capacity evaluation in the city is the basis of realizing water resources scientific management and water pollution comprehensive treatment. By stating the content and evaluation state of water environment bearing capacity, the paper analyzed the applicability and operability of various methods, selected model of artificial neural network (BP) and radial basis function (RBF) artificial neural network model to evaluate water environmental bearing capacity. The paper established the index evaluation system, domesticated BP and RBF model and calibrated parameter, finally, given the comprehensive pollution index of water environment, to study the water environment bearing capacity evaluation method in the city. The paper made Lishui city as the study region, the water environment comprehensive load state was weak load. The result demonstrated the feasibility of evaluation index and method.