Abstract: <FONT face=Verdana>Uses of polyferric sulfate (PFS) and its water purifying principle were introduced.Catalytic oxidation method is a PFS production mehtod which is making use of air or oxygen to oxidize ferrous ions into ferric ions under the action of catalyst (such as NaNO2 and HNO3),and then PFS could be produced by hydrolysis and polymerization.Direct oxidation method is through strong oxidants (such as NaClO,NaClO3,and H2O2) to oxidize ferrous ions into ferric ions directly,and then get PFS after hydrolysis and polymerization.Through the comparision and analysis on production processes,process control,production costs,advantages,and disadvantages of the two methods,it was found that direct oxidation method had better environmental and economic benefits due to its simpler production process,faster reaction rate,shorter production cycle,and smaller environmental pollution.</FONT>