Abstract: By co-polymerization,a series of high-concentration polyferric chloride (PFC) were prepared with ferric chloride and sodium carbonate as raw materials and W as stabilizer.The species distribution and transformation of iron in PFC have been studied by means of Fe-Ferron complexation timed spectrophotometry.The influences of the basicity ( B ),W/Fe molar ratio and aging time have also been studied.The results show that because of the interactions between the stabilizer W and the hydrolysate of iron in the hydrolysis-polymerization process of iron,the species distribution and transformation of iron change essentially.Basicity ( B ),W/Fe molar ratio and aging time all have influences on species distribution and transformation of iron in PFC.