Abstract: The macro-mechanical properties of cemented tailings backfill were affected directly by the kind and quantity of hydration products of cementitious materials and its microstructure.By means of XRD,TG-DSC,SEM,the relationships between macro-mechanical properties of cemented tailings backfill and the kind and quantity of hydration products were set in this paper.The results showed that the quantities of hydration products in cemented tailings backfill such as ettringite (AFt) was increased with cement-sand ratios and curing period,and the uniaxial compressive strength σ_c of cemented tailings backfill had a linear correlation with the quantities of AFt-x.The arithmetic expression is σ_c=2.0126x+0.5295,and its relative coefficience is 0.9610.Increasing the quantities of AFt can be helpful to improve the uniaxial compressive strength of cemented tailings backfill