Abstract: An effective method is proposed to simulate the action between the guardrail post and the foundation. The finite element software ABAQUS is adopted to analyzed the allocated spring element along the axial and the circumferential directions of the post. Horizontal distortion of the post will be generated when reaction applied on the spring element. In determining the results of numerical model for the effectiveness of the theoretical analytic techniques, the impacts of the number n of spring element and direction angle θ of load P are discussed. Meanwhile, the spring coefficient K_s and the analytical solution of the ultimate bearing capacity of arbitrary spring are gained. The number of spring element along the circumferential direction of the post in actual projects is also verified: when 8 or 12 spring element are arranged along the circumferenctial direction, the difference of the reaction of the spring system will become smaller owing to different loading directions. When 12 spring element are arranged along the circumferenctial direction, the load P under the same displacement is compared with that when θ=0°, the difference is within 2%. The results show that the post-foundation model is effective and feasible, and it can be used in the design of guardrail posts.