Yuanhe River is a major source of drinking, irrigation, industrial, hydropower generation, and recreational water for the circumjacent city. It has more serious water pollution problems because it flows through some heavy industry cities. So basis of the river water environment functional zones combined the various water quality data and the monitoring hydrological data, the water environment capacity of the Yuanhe River was calculated by using the one-dimensional water quality model. The results show that the water environment capacity is 112650 t/yr for chemical oxygen demand (COD) and 3265 t/yr for ammonium nitrogen (NH3-N). Most of the control units have residual water environment capacity, only individual control units have the serious water pollution and its residual capacity of COD and NH3-N is below 0, so it is necessary to strengthen the pollution control of these control units.