In order to improve the performance of cyclone separator in dust removal system，the research progress on the internal flow field distribution characteristics of cyclone separator is systematically expounded. The CFD software is used to numerically simulate the velocity field and pressure field，and the flow field law is revealed. The instantaneous physical quantities of fluids are measured by measuring instruments to reveal the flow field characteristics；Focusing on the velocity field and pressure field，the effect of velocity field on pressure drop energy consumption and particle separation efficiency is deeply discussed. The results show that tangential velocity is the key parameter to determine the separation efficiency，while the axial and radial velocity will cause the phenomenon of “ top gray loop” and “ short circuit flow”，respectively，which affect the direction of the particles. The pressure drop is controlled by the physical structure，fluid properties and operating parameters，and it depends on the velocity. Under the condition that the velocity field optimization target is not affected，the pressure drop should be reduced. Optimizing the structure and size of the feed port is an important method to increase the tangential velocity and suppress the phenomenon of “ top gray loop” and “ short circuit flow” . Optimizing the geometric parameters of the overflow pipe and adjusting the fluid properties （such as temperature and humidity） are effective ways to improve the separation efficiency and reduce the pressure drop of the cyclone. The results show that the combination of numerical simulation and artificial intelligence algorithms can achieve high-precision performance prediction and low-cost design optimization，and can provide theoretical basis and technical support for energy conservation and emission reduction in the steel industry.