Abstract: Structure of a typical dynamic liquid-liquid hydrocyclone. its numerical simulation model and boundary condition are introduced. The rationality of used numerical model and method are verified through comparing simulated value with test value. Parameters of hydrocyclone in length of rotating cylinder, quantity of rotating vane, length of rotating vane and diameter of overflow mouth are optimized, which lays a foundation for design and actual application of dynamic hydrocyclone in oilfield's production.