The numerical precision and the computation amount are limited by the dimensional steps of grid in the numerical simulation of hydraulics. There is always a conflict existing among the scope of simulation, the schematic dimensional grid steps and the total amount of the numerical simulation. Considering the spatial grid step, the time steps and the scope of numerical simulation, the author gives a general summary about the inter feedback nesting grid scheme for two dimensional hydraulic equations integrated in water depth in this paper. As an application example, the author sets up a numerical model with the inter feedback nesting grid scheme on the basis of the triangular elements method. The results and it show that the method can decrease the computation amount and improve the numerical precision.