Abstract: With 3D mixed element type unstructured grids, the numerical model that can simulate the 3D turbulent flow of spillway tunnel is established in this paper.The volume of fluid (VOF) method and the k-ε two-equation model for turbulent flow are adopted.The 3D Navier-Stokes equations are solved by using an improved cell-centered finite-volume method in order to eliminate the adverse influence of grid quality on stability and convergence speed.The comparison between the numerical results and the experiment data in spillway of Tankeng Hydropower Station shows a satisfactory agreement.