The paper is based on the state of water quality system of the lower sections of Chanba river. Considering from management point of view and the space dimension of water quality model, it selected the quality model of one-dimensional steady-state river water and chose parameter which is based on measured data of a large number of calibration. This paper set three conditions, such as investigation determined source, fixed licensing source and planning permission source witch were used to simulate the different section water quality of Chanba River downstream. By comparing the three kinds of impacts on water quality conditions, water is polluted under the conditions of investigation and licensing, while sources in the planning conditions would show a good water quality. The results can provide a basis for water environment management of the river.