The deposition law of tailings after discharge affects the stability of tailings dam. In order to study the characteristics of tailings deposition under different slurry discharge concentrations, this paper takes a tailings pond in Yunnan as the research object, and studies the tailings deposition law under different slurry discharge concentrations through field tests and indoor scale dam model tests. The critical state of single tailings particles is analyzed, and the relationship between the movement-deposition critical velocity of tailings particles and the migration distance formula of particles with different particle sizes on dry beaches are derived. The results show that there are more coarse tailings in the front of the dam of the sedimentary beach, and the farther away from the sub-dam, the more fine-grained tailings are deposited. The tailings flow velocity on the dry beach surface is negatively correlated with the slurry concentration and positively correlated with the tailings mortar pressure. The greater the concentration of the viscous high concentration tailings mortar, the weaker the flow force, and the greater the slope formed by the deposition; with the increase of slurry concentration, the deposition length of slurry also increases. The deposition distance of tailings particles on the dry beach surface is proportional to the initial velocity of slurry discharge, and inversely proportional to the dry beach slope, slurry discharge concentration and particle size. The research results can provide some reference for the stability analysis of tailings dam.