Abstract In order to improve the vertical and lateral load bearing capacity of the drilling conductor, composite design of bucket foundation and drilling conductor was studied. The bearing behavior of composite conductor subjected to lateral and longitudinal external loads was investigated. In this paper, the finite element analysis was conducted by two methods, load loading and displacement loading. The bearing capacity and influencing factors of composite conductor were studied with consideration of contact surface models of composite structures and surrounding soil. The results show that the vertical bearing capacity increase with the depth increasement of the bucket foundation under the combined bearing effect of the bucket foundation and the conductor. Meanwhile, the depth of the embedded point of the composite conductor increases with the bending moment when subjected to lateral loads. When the bending moment is constant on the structure top, the lateral displacement of the structure increases with the increase of the vertical force, and the depth of the embedded point increases with the increase of the vertical force. The results also show that the change of the bending moment at the top of the composite conductor is more significant than that on the lateral displacement. The composite foundation can effectively reduce the displacement of the deepwater conductor and improve the lateral and vertical load bearing capacity of the structure. And also the research results can provide theoretical reference for further development and optimization of the deepwater composite conductor structure.