In order to explore a new approach to the recovery and utilization of iron tailings from an iron ore dressing plant，the experimental process of preparing polymeric iron chloride from the acid leaching solution of the iron tailings was studied，and the self-made polymeric ferric chloride was applied to the coagulation test of kaolin suspension to test the flocculation performance of the product.The experimental results showed that the suitable conditions for polymerization were temperature 40 ℃，pH of 1.0，and polymerization time 3 h.Under these conditions，the alkalinity of synthesized polymerized ferric chloride was 20.91%，which met relevant standards，and the primary and secondary ranking of factors affecting the polymerization process were polymerization temperature，pH and polymerization time.The suitable conditions for coagulation were the dosage of polymeric ferric chloride of 250 mg/L，pH of 7.0，stirring time of 3 min，temperature of 20 ℃ and coagulation time of 60 min.Under these conditions，the turbidity removal rate was 95.54%，and the product had a good turbidity removal effect.