Due to the complexity of the fluid field in hydrocyclone and the difficulty of mastering the law of sediment motion, an Eulerian-Lagrange liquid-solid multiphase turbulence model combined with the kinetic theory of granular flow was used to carry out simulation based on coupled CFD-DEM watersediment twophase flow in a hydrocyclone, which analyzed the trochoid and speed of single sediment, speed of sediment group, the moving pattern and distribution of sediment group. The simulation results show that the smaller the sediment size was, the closer the distance was, the more easily uprising from downward trend to upstream, and the more difficult to be separated. For the particles of 40μm in diameter, sediment peak appeared in the interface of cylinder and cone and the separation effect of sediment was easy to be affected. But for the particles of 50μm and 60μm, sediment peak appeared in cone part and sediment had a better separation effect. Through tracking single sediment and sediment group, it can be found that the sediment almost stay in circular motion in cylinder. In cone part, sediment not only stays in circular motion but also obviously runs in line movement when they enter in sediment settling. Analyzing the moving pattern and distribution of single sediment and sand group provides a microscopic method for understanding separation efficiency and also provides an effective research method for the further study of the hydrocyclone performance.