Abstract: The mechanical properties and microstructure of as-welded,as-annealed and as-rolled stainless steel-carbon steel composite plates produced by explosive welding were investigated by SEM and mechanical tests. The element diffusion of transition layer formed in explosive welding was measured by EDS linear scanning. The results show that both the annealing and the hot-rolling can reduce the tensile strength and yield strength of the composite plates,but improve the ductility and toughness of the composite plates. The microstructure of the transition layer of as-welded,as-annealed and as-rolled composite plates are different. The wavy interface of the as-annealed composite plate is similar to that of as-welded composite plates. The diffusion layer with thickness of only about 5 μm is formed. For as-rolled composite plate,the wavy interface disappears and the diffusion layer enlarges to about 20 μm in width.