Abstract: In order to study the influence of vehicle load on the stability of highway retaining wall, introduce an improved equivalent soil thickness method which based on the Coulomb earth pressure theory and iterative calculation of fracture angle convergence value to get a new converted soil thickness. Combined with the example of a retaining wall of Ankang Highway, the results show that the improved method is more accurate in evaluating the stability of the retaining wall. Using the numerical method to analyze the mechanical response of the retaining wall under vehicle load, and it is considered that the affected part of the retaining wall under the vehicle load is mainly the upper middle part. The smaller the distance between the car and wall is,the more significant the vibration response of the soil behind the wall is, and the greater the additional dynamic earth pressure is,but the horizontal displacement of the retaining wall is not greatly affected by it.