In order to study the problem of solving the active earth pressure of retaining walls in RB mode, this study assumes that the slip crack surface is a curved slip crack surface, proposes the calculation method of active earth pressure in RB mode, derives the differential equation of active earth pressure by using the horizontal stratification method, and solves it by the finite difference method, and compares the calculation results with the relevant test results to verify the accuracy of the method. This study also discusses the effect of wall top displacement on the pressure distribution of the active soil, the magnitude of the combined force and the location of the point where the combined force acts. The results of the study show that there is a negative correlation between all three of these and the top of wall displacement.