Abstract: The history and the current status of vortex pump were briefly introduced. A 3-D model of the internal flow channel of the vortex pump typed WQX20-16-2.2 was firstly constructed. Then, by taking the volute and the impeller as a whole, the internal 3-D incompressible turbulent field has been numerically simulated using the unstructured grid generation technique. Finally, the internal velocity and pressure distribution in the volute of vortex pump has been achieved by using the SIMPLE algorithm and the turbulent flow model, which is based on Reynolds time-averaged equations and two-equation. The further analysis of the above distribution fields indicates that a considerable amount of radial vortex and axial vortex exists in the volute of vortex pump. This result has not only proved the validity of the flow models put forward by other authors, but also provided a basis for further design improvement of vortex pump.