Making hydrochloric acid directly react with pyrite tailing under atmospheric pressure and by polymerization, a polymeric aluminum ferric chloride (PAFC) is prepared.Optimum techno1ogical conditions of preparing PAFC with pyrite tailings were obtained through researching the influence factors of A1_2O_3, Fe_2O_3 dissolving rate. The new PAFC has a high performance of removing the turbidity of wastewater.