The secondary flow effect existing in the hopper of the cyclone caused the captured particles to re-enter the airflow, which decreased the separation efficiency of the cyclone. In order to effectively suppress the secondary flow effect in the hopper, the two-phase flow numerical simulation study of the cyclone with different geometric dimensions and installation positions of the apex cone was carried out by means of built-in apex cone. The results showed that the built-in apex cone reduced the tangential, axial velocity and turbulence intensity of the flow field in the hopper, and had a significant suppression effect on the re-entrainment caused by the secondary flow in the hopper of the cyclone. The simulation results recommend that the optimal angle of the apex cone was 80?, and the best installation position was that the vertical distance between the bottom surface and the cone section was 0.375B≤Bs≤0.5B. When the inlet velocity was 12 m/s, compared with the original structure, the overall separation efficiency was improved by 11.50%, and the pressure drop increased by 8.29%.