Abstract: In this article, the deformation mechanism of gravel pile composite foundation is thoroughly examined. The dilatancy of Mohr-Coulomb elastic-plastic materials and the three-fold line model are adopted to optimize this research. The radial bulging of the physique gravel pile which bears the upper loads is taken as the hole expansion. The elastic and plastic zones are divided into two parts and the stress field along with displacement field of the soil around the piles in the elastic and plastic zones is respectively established by suing the Vesic circular expansion theory. The influence of the earth pressure is assumed as the static earth pressure and the calculation formula of the bearing capacity of the single pile of gravel pile is obtained by combining the formula of passive earth pressure. In order to verify the feasibility of this method, this paper is combined with the actual engineering data on the derived bearing capacity calculation and good agreement is found between the results obtained with the proposed data. The results show that the calculated values are in good agreement with the measured values, indicating that the proposed method is reasonable.