The disposal of acid wastewater generated by a copper-nickel smelting enterprise by using abandoned tailings mortar combined with sulfide precipitation and coagulation indicated that this method has demonstrated good results: the effluent can acheive “Emmission standard of pollutants for copper, nickel, cobalt industry” (GB 25476-2010); the heavy metals in the sediment is not apt to experience dissolution, thus less possible for secondary pollution of soil and groundwater. The optimal combination conditions of this process for sludge/wastewater mass ratio is 14:1; sodium sulfide’s dosing is 20 ml, reaction time is 20 min; FeSO4 and acid waste water volum ratio is 0.05, the reaction time is 30 min.