In order to fully utilize the high strength of the cemented soil pile/wall, a retaining structure with soil nailing wall combined with cemented soil pile/wall for deep excavation is proposed and its design philosophy is discussed in this paper. Based on finite element numerical simulation combined with the typical geological condition of Nanchang area, the distribution characteristics of seepage flow, horizontal soil displacement, axial force of soil nail, stress of cement-soil pile wall and the failure mode as well as the influence of bottom reinforcement and cement-soil pile wall distance of the novel structure on the support performance are systematically studied. Meanwhile, comparative analysis with the traditional soil nailing wall structure and the composite soil nailing wall structure are conducted. The results show that: Under the condition of ensuring the safety of the wall, the support mechanism of the novel structure is more reasonable due to the horizontal displacement of the soil at the excavation face and the axial and tangential stresses of cement-soil pile wall much smaller than that under the traditional soil nailing wall structure and the composite soil nailing wall structure; the failure mode of the foundation pit is similar with that under the gravity retaining wall support method, and reinforcement of the pit bottom can significantly improve its support performance.