Abstract: The suitable preparation conditions and flocculation properties of ferric chloride and starch composite flocculant were studied. The results showed that when the ratio of V (modified starch solution) to V (ferric chloride solution) of the preparation system was 0.5, the preparation temperature was 45 ℃, the reaction time was 3 h, and the ripening time was 18 h, the flocculant prepared had good flocculation effect. When 200 mL tailings water is treated with this flocculant, the pH value of tailings water is 7, the dosage of flocculant is 21.18 kg/t, and the flocculant flocculates for 60 s, the turbidity removal rate can reach 98%. The results of infrared spectrum analysis showed that the ferric chloride and starch were not simply mixed, but condensation polymerization and coordination reaction occurred, which enhanced the adsorption and bridging effect.