Abstract: In order to solve the technical problems of rapid concentration, continuous sand discharge and filling operation of full tailings in the vertical sand bin for a mine, and the experimental study on flocculation and settlement of full tailings in vertical sand silo should be carried out to optimize the selection.In this study, the variation of the settling surface height of tailings with time is studied from three aspects:flocculant selection, different adding ratio of flocculant and optimal sand supply concentration.The results show that the mass concentration of backfilling too low or too high are not equilibrium concentration of subsidence velocity and subsidence gap in for sand concentration is 15%, add 5 million molecular weight of anionic polyacrylamide (APAM) with adding a ratio of 5 g/t, the sedimentation velocity of 686.89 cm/h are obtained, it can realize the requirements for dynamic subsidence of full tailings and continuous sand discharge.