Abstract: In order to bring to light the law governing the distribution of flow field of the cyclone separator in powdered coal pyrolytic system,a RSM turbulent model is established with the cyclone separator in field use as object. The numerical simulation of the separator’s flow field is conducted using the QUICK format for the discrete convection term and the PRESTO format for the pressure gradient term. The analysis made on distributions of tangential velocity and axial velocity,and turbulent structure of the flow field indicates that by using the numerical simulation method,the law governing the distributions of the tangential velocity and axial velocity,and the turbulent structure of the flow field can rationally be revealed. This provides a basis facilitating the subsequent modeling of particle field.