The Large Eddy Simulation (LES) method is one of the latest turbulence numerical calculation methods in the field of computational fluid dynamics. It solves the large-scale flow in water and air and simulates small-scale eddies, while taking into account the accuracy of turbulence calculation and engineering applications and economy. In recent decades, LES has been increasingly used as an important tool to solve water conservancy and environmental engineering problems, such as the problem of sediment transport in water, the transport of pollutants in water and the atmosphere.This course is divided into three parts: 1) The basic principles of the large eddy simulation calculation method are described in detail; 2) The application results of the large eddy simulation technology in the field of hydraulics are systematically reviewed in recent decades; 3) Commercial software for LES. It is designed to enable students to understand a principle and method of computational fluid dynamics, to broaden the horizons of scientific research, and to master a practical numerical calculation software.