Abstract: The stainless steel/low alloy steel composite plate was prepared by the combined billet making process of submerged arc welding and vacuum electron beam welding. The influence of hot rolling, solution and tempering processes on the composite plate matrix, composite structure and corrosion resistance was analyzed. The results show that after heat treatment, the element diffusion area of the composite plate becomes wider. After solution at 1100 ℃, carbides such as Cr₂₃C₆ are dissolved in austenite grains, and the tendency of intergranular corrosion is greatly reduced. After high temperature tempering treatment, the structure of composite plate changed from martensite to tempered sorbite. Under 650 ℃ tempering process, the intergranular corrosion resistance of stainless steel is significantly improved compared with that of hot rolled steel,and the electrochemical corrosion rate is reduced from 1.42×10^-2mm/a to 1.14×10^-2mm/a. At 1100 ℃ solution and 650 ℃tempering process, the composite plate has excellent corrosion resistance, while the shear strength of the interface reaches 480 MPa. The strength, plasticity and toughness of the composite plate can meet the requirements of the national standard.