Abstract: In order to fully understand the distribution of the internal flow field of micro-irrigation with gravel filter, using the same mathematical principles herein FloEFD fluid of CFD simulation software, using porous media model, the sand and gravel filter bed resistance characteristics as a boundary condition of three-dimensional numerical model and numerically simulate the full flow field inside the filter. The results show that the boundary conditions of the internal components of the filter and the water outlet have a great influence on the distribution of the velocity flow field and pressure field of the filter. The computational fluid dynamics method based on the porous media model has a high accuracy in the numerical simulation of the sand filter. simulation and experimental results of the method are in good agreement, we can accurately predict the performance of the hydraulic filter.