In order to ensure the water environment quality to be healthy in Jiashan, the center of border-crossing section of Jiangsu, Zhejiang and Shanghai, the total amount control method using important border-crossing sections as the water quality control factors is promoted, considering the particularity of the location of Jiashan. A one-dimensional mathematical model of water environment in Jiashan region was established based on the data including survey in Jiashan section and hydrology and water quality monitoring data. Hydrodynamic and water quality model parameters in Jiashan region are determined. 4 border-crossing sections in Jiashan region are selected as the control sections. Water quality simulations are conducted under different cutting schemes for the water environment, using one-dimensional mathematical model of water environment, which is calibrated and proved to be reasonable. The results of the simulation indicate that: the total amount of ammonia nitrogen needs to be reduced by 14. 2% and the total amount of COD needs to be reduced by 37. 7% in Jiashan region, to guarantee the water quality in the important border-crossing sections reaching the standard.