Abstract: Blocks are used at stilling basins to decrease the high flow velocity and dissipate energy at hydraulic structures. In this study, a comparison between physical and Computational Fluid Dynamic (CFD) Model at stilling basin blocks are conducted. The aim of percent CFD Model is to show the application of the finite element method for the solution of fluid flow problems. In addition, investigate and validate theoretical work by ANSYS program solutions with previous experiment results. A free surface (CFD) Model based on the Volume of Fluid (VOF) method and characteristic of the turbulence k–g Model has been applied. Finally, the results of physical model and (CFD) have been compared to study whether the results come to a good agreement.