The gas-solid two-phase flow in the guide vane cyclone tube with different dust discharge structure is studied by numerical simulation method.The studies show that the downward flow and upward flow pass through the same discharge section of the cylinder type discharge structure，so the upward flow may entrain fine particles from the hopper and result in poor performance of the cyclone.With the cone shape discharge structure，the gas flow rotation in the cyclone is improved and the downward flow can be controlled，which is helpful to obtain better performance.However，vortex flow is found in the discharge cone，which will cause flow erosion to the wall of cyclone tube.The opening slots in the wall of discharge cone can change the state of gas-solid two-phase flow，which give different paths for discharge flow and upward flow，stabilize the flow in the hopper，avoid the entrainment of particles from the hopper，so that the performance of cyclone tube is improved.