Abstract: In order to optimize the design of the reversible pump-turbine runner,the flow characters on the whole flow passage including the runner should be understood.The SIMPLEC algorithm and the Standard k-ε Turbulence model are applied to carry on the three-dimensional two-way numerical simulation on the whole flow passage of a high-head reversible pump-turbine runner,which is designed with the full three-dimensional reverse design method.The current situation of the volute,tail and the runner interior is analyzed in detail.The hydraulic losses of different parts and the performance of the runner are also estimated.The result reveals the interior flow complexity of the pump-turbine runner,and the relations and influence of different parts,which leads to an improved runner design.