Abstract: Large eddy simulation of film cooling over flat plate with 30° streamwise inclined cylinder hole was performed to investigate the turbulence field of film cooling.The Reynolds number at the jet exit was 2 600,and the blowing ratio was 0.5.Numerical results show that flow separation in the hole increases the turbulence kinetic energy and results in the decrease of film cooling effectiveness,which should be avoided as much as possible in design of coolant supply plenum.Eddy viscosity coefficient relevant to the lateral diffusion of film has peak on both sides of the hole,while the peak predicted by isotropic eddy viscosity model is in the shear layer between mainflow and jet.This results in the overprediction of vertical penetration and underprediction of lateral spread of the jet.Large eddy simulation can be used to construct anisotropic turbulence model in order to improve the accuracy of turbulence model.