Abstract: In order to research the influence of flow structure of rotating-bar on the flow field within 3 kind of deoiling dynamic hydrocyclones (vanetype, spiral type and straight-through type), flow fields are simulated based on the computational fluid dynamics method. Reynolds stress model and mixer model of multi-phase models are used in the calculation. The results show that the rotating-bar has a huge impact on the turbulent intensity and dissipation. Moreover, the turbulent intensity around the spiral-type rotating-bar of dynamic hydrocyclone can be controlled or weaken. The straight-through type rotating-bar can generate larger tangential velocity and axial velocity, and has stronger separation capability and wider efficient separation domain than the other.