In order to meet the demand of high-performance shaft parts for Marine engineering equipment under high salt and high-pressure environment, in this paper, the cross-wedge rolling (CWR) method is used to prepare 34CrMo1/316L bimetallic composite shaft. Based on the thermal compression test, the harmonious deformation law of the two materials was investigated. The forming of composite shaft is studied by means of wedge rolling experiment and finite element analysis. The interface properties of composite axes were characterized by shear tests. The microcosmic analysis of the interface region is carried out. The results show that: Deformation temperature, deformation amount and deformation rate significantly affect the deformation coordination of the two materials. The composite shaft is well formed in the process of forming temperature of 1000∼1200 °C, area reduction of 50∼60 %, coating thickness of 2∼3 mm and rolling speed of 15∼20 rpm. The shear strength of the composite shafts with good macro forming reaches more than 70 % of the substrate. Element diffusion occurs at the bonding interface, and elements diffuse downward from the high concentration region to the low concentration region. A clear bonding layer is formed between the two materials. Most of the grain boundaries on the side of the cladding material (CM) are high angle grain boundaries (LAGBs), while most of the grain boundaries on the side of the substrate material (SM) are low angle grain boundaries (LAGBs). The grains of the two materials at the bonding interface are refined and cross randomly distributed, which makes the interface slightly curved. In this study, the bonding process of CWR composite shaft was analyzed from multiple perspectives, which revealed that the interface bonding mechanism of the composite shaft is simplified into three stages: contact stage, interface activation stage and diffusion bond stage.