Abstract: Mixed tannins and heavy metal ions form large molecular flocculates with a ring structure were precipitated and separated from water bodies. Two kinds of wastewater were mixed in a certain proportion,and the purpose of treating the two kinds of wastewater at the same time could be achieved through neutralization,coagulation and precipitation. Experiments have shown that the removal rates of major pollutants such as Cu²⁺. Pb²⁺. Zn²⁺and Cr²⁺were all more than 90%.