Abstract: It is of great guiding significance for the design of gravity anchorage to explore the bearing mechanism of gravity anchorage foundation system of suspension bridges. Based on numerical experiments,the influencing factors and laws of the bearing performance of the anchorage foundation system were studied,for the typical working condition,the bearing behavior of the anchorage foundation system was further analyzed,combined with the calculation results of Hansen formula,the bearing mechanism of gravity anchorage foundation system was discussed. The results show that,the limiting effect of surrounding rock and soil can greatly improve the ultimate bearing capacity of anchorage foundation system,it is necessary to consider making full use of the bearing capacity of the surrounding rock and soil in the design of gravity anchorages. The mechanical properties of the foundation rock and soil have a significant impact on the bearing performance of the anchorage foundation system. It is recommended that the types of rock and soil be strictly distinguished when the bearing capacity of the foundation is considered in the design. The cable force load action mode also has a significant impact on the ultimate cable force load and the anchorage-foundation failure mode. In the anchorage design process,it is necessary to further determine the IP point position according to the physical geometric parameters such as the main cable incident angle,and make full use of the bearing capacity of the anchorage itself. The calculation results of the Hansen formula and numerical simulation can preliminarily reveal the influencing factors of the bearing performance of the anchorage-foundation system,with the increase of cable load,the tangential force and normal force of the foundation base under the action of the ultimate cable force decrease sharply,and a sliding failure surface is formed in the rock and soil mass,leading to the instability and failure of the anchor foundation system. The shape of the sliding failure surface is the main controlling factor of the ultimate bearing capacity of the anchorage foundation. The research results can provide theoretical analysis basis and mechanism understanding for the design of gravity anchorage.