Abstract: To solve the problems of irregular boundaries and free surfaces in CFD (Computational Fluid Dynamics),a modified κ-ε turbulence model is derived,and the governing equations of turbulent flow over irregular boundary are developed by analyzing the solid-liquid two-phase theoretical flow model.And furthermore a partial-cell parameter is introduced to treat irregular boundary.To track free surfaces,a simple but powerfule method is described that is based on the concept of fractional volume of fluid (VOF).By using the established computer code,several typical examples in hydraulic engineering are studied numerically,the results of which are in agreement with experimental data.