Research conclusions: The soil pressure weight and pressure distribution of rigid retaining wall relate to the displacement way，the wall SUrface friction characteristics，and soil deformation characteristics of the retaining wall and other factors．The flexible retaining wall has the soil pressure with non—triangle distribution，and its soil pressure weight and pressure distribution relate to whether the soil body to achieve the limiting balance status，the displacement and creep deformation of soil body，construction procedure and the depth of foundation pit．The finite—element method plays the great role in calculating the soil pressure and with it the construction procedure can be simulated and the influence factors of time and non—linear displacement can be considered in calculation of soil pressure to solve the non—linear problems，such as heterogeneous material，complicated boundary and all isomerism．The appearance of contact unit makes the simulation more close to the real situation．