The effect on the removal of organic substance from the Huangpu River water by enhanced coagulation is investigated. Although both of the increase of dosage and the decrease of pH can enhance the removal of organic substance effectively, the decrease of pH can remove organic substance more effectively. The dosage of coagulant required for optimum removal rate is different for different pH value. The lower the pH is, the less dosage is required. For the Huangpu River water, when the dosage 8 mg/L (as Al) and pH 5.5, the optimum removal rates of DOC and UV₂₅₄ are 46% and 57% respectively, which doubles the removal rates of conventional treatment. Enhanced coagulation can also remove disinfection by products(DBPs)effectively.