Abstract: With the progress of beneficiation technology,the proportion of fine-grained tailings produced by the concentrator increases gradually,and the strength of underground backfills decreases.To meet the mine’s requirements for the strength of underground backfills,the content of cementitious material has to be increased,which increases the filling cost and affects the mine’s income.Given the problems existing in the cementitious filling body in Jinfeng Gold Mine,this paper proposes to optimize the cementitious material used and use cementitious powder to replace cement as the cementitious material for filling.The filling mix proportion test on the cementitious powder and cement is carried out to verify the feasibility of cementitious powder replacing cement as cementitious materials.On this basis,the mix proportion optimization test on the cementitious powder is carried out separately.The results show that when the slurry concentration is 65 %,the 5.5 % cementitious powder addition can meet the requirement that the 7 d uniaxial compressive strength in the underground Jinfeng Gold Mine is 0.35 MPa.The analysis in terms of economic benefits found that using cementitious powder instead of cement as cementitious material can save filling costs by 9.5 million yuan/a.