Fly ash is one kind of common industrial solid wastes,but can be reused as secondary owing to its potential binding capability.The physical and mechanical properties as well as chemical components of the filling aggregate and fly ash were measured and analyzed.On that basis,experiment was made on mixing ratio of backfill materials.It was found that if weight percentage among cement,fly ash and aggregate was 1:2:6,the cement consumption could be reduced by 26% and backfill cost could be saved by about 10%.More important,backfill body with suggested dosage had higher long-term compressive strength and final strength could be increased nearly one time.Application of cemented backfilling with this mixing ratio in Gaofeng Corporation has resulted in excellent economic and social benefit.