Abstract: Through field loading tests on vehicle, the acceleration under loading conditions and soil pressure behind piles is determined, an equation for the vibration acceleration changes over time is obtained, and the vibration characteristics of the vehicle are analyzed. Based upon the limit equilibrium method, a method is proposed for calculating the dynamic earth pressure on piles under vehicle loading. The effects of a wide range of parameters like vibration acceleration coefficient, wall friction angle, soil friction angle, and the weight of the soil on the active earth pressure are studied. The results show that the peak acceleration and the amplitude of dynamic soil pressure increase with increasing vehicle speed. When the speed is the same, the dynamic soil pressure is attenuated very fast with the spacing between the loading vehicle and the pile, which is changed in a sinusoidal fashion. Through validation, it is indicated that the measured earth pressure accords with the theoretical analysis. Therefore, the proposed method may provide a basis for the calculation of active earth pressure on supporting piles under vehicle load.