Abstract: A concept of "two-layer" turbulence model is proposed which employs an algebraic turbulence model in near wall area and a two-equation turbulence model in outer area or far wall area.The flows over a flat plate with M =0 3 uniform inflow and in a 90°rectangular bent duct with non-uniform velocity and high turbulence inflow are calculated respectively by use of the "two layer" turbulence model and two equation turbulence model with low Reynolds number modification.The obtained results show that the "two layer" turbulence model can predict the distribution of velocity and wall stress for external flow and the boundary layer thickness and main velocity for internal flow more accurately than the two equation turbulence model.Therefore the "two layer" model is a powerful tool in engineering.