Abstract: The flow field and erosion characteristics of a cyclone separator were numerically simulated by Oka erosion model and computational fluid dynamics (CFD) technique. The distribution of flow field and other parameters in the cyclone were analyzed with the increase of erosion thickness. Effects of cone local erosion on the flow field and performance of the cyclone were studied. The results show that a spiral erosion zone forms on the wall of the cyclone separator, and the local erosion at the bottom of the cone near the dust outlet is the most heavily affected. The change of wall geometry caused by erosion reduces the tangential velocity and centrifugal force on particles, enhances the local vortex strength in the cone, and increases the influence of vortex core precession (PVC), which are not conducive to the stability of the mainstream and the separation of solid particles. Compared with no erosion, the particle separation efficiency of 4 μm particle decreased from 100% to 93% when the local erosion thickness was 20 mm. The cut off diameter increased from 1.3 to 1.9 μm, and the pressure drop of the equipment decreased by 40%. This work has important theoretical significance for ensuring the long-term safe and stable operation of cyclones.