Abstract: Compressive strength is an important index to characterize the mechanical properties of cemented backfill.It is the basic basis for determining the filling scheme of the stope.Therefore，it is of great significance to determine the compressive strength value of cemented backfill quickly and accurately.The influencing factors of the strength of cemented backfill are discussed，in order to overcome the inaccuracy of single prediction factor and complexity of excessive prediction factors，two parameters of initial ultrasonic wave velocity and density of cemented backfill that are easier to obtained are selected.The wave velocity-density double parameter prediction index T is established，then，the strength prediction model of cementation backfill is indicated by using the predictive index，and the performance of the model is verified.The study results show that:①the influence factors of the uniaxial compressive strength of cemented backfill including composition，structural size and curing environment，the main influencing factors is composition；②curve fitting analysis of the test data is done by using the strength prediction model established in this paper and typical strength prediction respectively，the comparative analysis results show that the curve fitting effects of the newly established model is better than the other，the correlative coefficient is above 0.98，which further indicated that the strength prediction model newly established can effectively predict the strength of cemented backfill.The above study results indicated that the it is feasible to predict the strength of cemented backfill with two parameters of wave velocity and density，therefore，the new ideal for accurately predicting the strength of cemented backfill.

Key words: Filling mining, Cemented backfill, Ultrasonic velocity, Density, Strength prediction