A three-dimensional Large Eddy Simulation (LES) has been performed of hydrodynamic behavior of turbulent flow in open channel that the lower part of the domain is occupied by a drag force layer to represent vegetation. One equation model is used to closing the resolvable scale equations. The turbulent characteristic length is parameterized by a k-l model. A phenomenal model is employed to express the performance of vegetation in the open channel. The result reveals that the present model has the capacity of describing three-dimensional structure of large eddy appearing in turbulent flow in open channel with vegetation region and has the capacity of tracing the development of large eddies. A three-dimensional Large Eddy Simulation (LES) has been performed on hydrodynamic behavior of turbulent flow in open channel that the lower part of the domain is occupied by a drag force layer to represent vegetation. One equation model is used to closing the resolvable scale The turbulent characteristic length is parameterized by a kl model. A phenomenal model is employed to express the performance of vegetation in the open channel. The result reveals that the present model has the capacity of describing three-dimensional structure of large eddy appearing in turbulent flow in open channel with vegetation region and has the capacity of tracing the development of large eddies.