Abstract: A new type of flocculant - polyzinc silicate sulfate (PZSS) with different concentrations of SiO2，Zn/Si molar ratios，polymerization times and pH values were prepared and the effects of such preparation parameters on the structure were studied with IR spectroscopy. The results showed that the structure of PZSS was dependent on the concentration of SiO2，molar ratio of Zn/Si，polymerization time，pH value and so on. It was proved by IR spectroscopy that Zn2+ and hydrolyzed ion were chelated with polysilicic acid to produce the polymer of zinc-silicon. The reaction was not the simple physical blending，but the chemical reaction forming the inorganic polymer with special structure. The better flocculating efficiency was resulted mainly from the chemical and physico-chemical factors among the components.