Polymeric aluminium iron chloride produced by Xinhuan Water Treatment is a kind of polymer coagulant developed on the basis of the mechanism of coagulation and hydrolysis of aluminium salt and iron salt. Polymeric aluminium chloride is brown, reddish brown powder or grain, very soluble in water. Polyaluminum ferric chloride is a new type of high-efficiency coagulant compounded by adding single iron ion and other iron-containing compounds. And the introduction of polyvalent anion a sulfate ion, the morphology of aluminium ions and iron ions have obvious improvement, it has the respective advantages of aluminium salt and iron salt, the morphology of aluminium ions and iron ions have obvious improvement, the degree of polymerisation is greatly improved.