High accuracy performance prediction method based on entire flow passage for a Francis turbine is presented. The performance is predicted by solving unsteady Reynolds-Averaged Navier-Stokes equations combined with Reynolds- Stress model and Bubble two-phase flow model. The prediction accuracy was evaluated to compare with the model test results for three different specific speed turbines. By comparing the simulation results with model test results for efficiency characteristic, pressure fluctuation characteristic and cavitation characteristic, it was proved that numerical model test presented in this paper could predict important characteristics of Francis turbine with high accuracy not only quantitatively but also qualitatively. As a result, it was concluded that numerical model test is going to be a more realistic estimation tool for hydraulic performance of Francis turbine and hence contributes to cost reduction in the development of Francis turbine.