Abstract: Coal gangue is a by−product generated during the mining and washing processes of coal mines, which is rich in silicon, aluminium and iron. Titanium slag is produced in the titanium extraction process of ilmenite smelting, and its titania content is usually over 20%. In order to realize the resource utilization of coal gangue and titanium slag, an inorganic coagulant, i.e., polyaluminum ferrotitanium sulfate (PAFTS), was prepared from coal gangue and titanium slag by thermal activation, modification, ageing, polymerization, centrifugation and drying. The effects of the preparation factors such as the molar ratio of titanium to iron (Ti/Fe), polymerization solution pH, polymerization time, polymerization temperature, ageing time and ripening temperature on the coagulant were investigated. Additionally, the influence of coagulant dosage, initial pH, slow stirring time (50 r/min) and standing time on the coagulation performance of PAFTS were explored using simulated wastewater prepared by kaolin. The optimal preparation factors and coagulation conditions were thus determined. The results show that the best coagulation performance of PAFTS is achieved at a Ti/Fe molar ratio of 0.4, polymerization solution pH of 1.5, polymerization time of 4 h, polymerization temperature of 70 ℃, ripening temperature of 40 ℃ and aging time of 24 h, and the removal of turbidity, COD and UV₂₅₄ of the simulated wastewater are 96.0%, 46.0% and 41.0%, respectively, under the conditions of 100 mg/L of PAFTS dosage, reaction solution pH of 7, 10 min of slow stirring time and 30 min of standing time, and the preparation cost of PAFTS in the laboratory is approximately ¥87.5/kg. Subsequently, the optimum working conditions of PAFTS prepared in the above optimal preparation condition are obtained at 80 mg/L of PAFTS dosage, initial pH of 7, 15 min of slow stirring time and 20 min of standing time, which results in 97.9% removal of turbidity. This work provides a method for the preparation of polymetallic coagulant and a new idea for the resource utilization of coal gangue and titanium slag.