Abstract: To decrease the water pollution of the Fujiang river within the administrative district of Mianyang, the standard exponent method was used to appraise the water quality.Nine functional water areas were partitioned, different models based on the characteristics of each area were constructed, and the water environmental capacity (WEC) of the river was calculated respectively using one-and two-dimensional models to decrease the error of calculation.Finally, the residual WEC was distributed in administrative districts.The research results show that the water quality of the Fujiang river has been polluted by organic objects, and its chemical oxygen demand and ammonia-nitrogen are respectively 56 142 and 3 109 t/a.The research provides a reference for water environmental management and control of the Fujiang river.