In this paper, the Large Eddy Simulation (LES) flow modelling method is applied to solve the Navier-Stokes equations. In which, the influence of the stress components of the small structures is modelled by the Smagorinsky flow model. This mathematical model is applied to the flow through a square cylinder with two different Reynolds number conditions Re = 400 and Re = 22,000. The calculated results of the average flow as well as the characteristics of the multi-dynamic components are compared with the results calculated by the DNS (Direct Numerical Simulation) method and the k- model, showing the advantages of this method. At the same time, these results also have a compatibility with the experimental results under the same Reynolds number conditions.