Rapid flocculation and settlement (FS) of mine tailings is significant for the improvement and development of the filling process, whereas the settlement velocity (SV) of tailings in FS has been recognized as a key parameter to evaluate the settlement effect. However, the influence of temperature on the SV and its mechanism have not been studied. FS experiments on tailings with various ambient temperatures were carried out. The SVs of tailings with a solid waste content of 10wt％ and an anionic polyacrylamide content of 20 g·t?1 were measured at different temperatures. The SV presented an “N”-shaped variation curve as the temperature changed from 5 to 40℃. The mechanism of these results can be explained from the perspective of the electric double-layer repulsive force, molecular dynamics, and the polymer flocculation principle, as revealed from the scanning electron microscopy of floc particles. The findings will be beneficial in the design of tailings dewater-ing processes and save costs in the production of cemented paste backfill.