This paper presents a numerical study of the gas-particle flow in a typical divergent cyclone. The gas flow field is obtained by the use of Reynolds stress model (RSM) and the particle motion is simulated by the use of a stochastic Lagrangian model. Both the axial velocity and tangential velocities decrease from top to bottom as a fluid segment moves due to the inverted conical cyclone body. Only a few gas streams can enter the dust hopper due to the blocking effect of reflecting screen. Almost all particles with big diameters (d >= 5 mu m) are collected by the divergent cyclone. The divergent cyclone also has strong capability to trap the particles with small diameters (d<5 mu m) because particles may have little chance to escape from the dust hopper due to the blocking effect of reflecting screen. In condition of the relationship between separation efficiency and pressure drop, the operating gas inlet velocity range is suggested to be 14-18 m/s. 2011 Elsevier B.V. All rights reserved.