The bonding quality of bronze/steel bimetallic laminated composite is the key factor to whether it can be used in poor working conditions. In this study, bimetallic billets were prepared by the protective atmosphere casting process. The microstructural characteristics, mechanical properties and interface bonding mechanism of the bronze/steel bimetallic composites were analyzed comprehensively through a series of microstructure analysis (inicluding OM, SEM, and EDS) and mechanical properties tests. The experimental results demonstrate that the vaporization of lead (Pb) element in the bronze is only 0.4％ in weight, and alloy elements are diffused into both sides at the interface. Moreover, the hardness in the bronze region exceeds 100.0 HV which indicates excellent wear resistance. Tensile and shear tests indicate that the fractures mainly occur on the bronze side with the interaction of the brittle fracture of Pb particles and the ductile fracture of Cu-Sn solid solution. The maximum tensile strength and shear strength reach 204.0 MPa and 211.0 MPa, respectively. These results demonstrate that the protective atmosphere casting process is applicable for the preparation of bronze/steel bimetallic laminated composite with high quality.