According to the Jiangsu water function zonation,combining with the current of water quality and pollutant in Wujiang, the paper used water quality parameters calibrated by river-dimension model to calculate the water environment capacity and limited gross of water pollutant discharge in water function zone of Wujiang. Compared with the amount of present pollutant discharge into account in Wujiang,it calculated the amount of pollutants to be reduced, so as to provide method and theoretic basis for water pollution control and reduction of pollutant in Wujiang. The results show that the water environment capacity of CODCr and NH3-N in Wujiang are 17344 and 1672 tons per year respectively, which are 60% and 54% of total amount of present pollutant discharge. The pollutant reduction rates of CODCr and NH3-N are 54% and 56% that are consistent with the present pollutant discharge and the excess rate of water quality. The calculation results of water environment capacity and limitation of water pollutant gross are reasonable.