Poly Ferric Sulfate (PFS) is a complex ferric material. The molecular formula is the [Fe2 (OH)n (SO4)3-N/2]m, n＞2; m=f (n). There are a lot of complex ferrous ion ([Fe2 (OH)3]3+, [Fe(H2O)6]3+, [Fe3(OH)3]6+) in its water solution. So it is a good coagulant which has strong flocculation and has a good coagulation. Its chemical structure is a solid network polymer which has a multinuclear complex ion. It can be easy to hydrolyze in water and can produce the highly efficient multinuclear hydroxyl complex positive ion. In the process of water treatment, Polymer ferrous sulfate has a good ability to neutralize surface electric charge of suspended substances, and linking suspended particle. PE drum.