For the problem that stress relief annealing has a great effect on corrosion resistance and mechanical properties of the C-276/Q235-B bimetallic composite plate, the microstructure and mechanical properties of the C-276/Q235-B bimetallic composite plate at different heat treatment processes were investigated in the present investigation. The results showed that after 560°C,580°C and 600°C heat treatment, the tensile strength of composite plate was in 515-530MPa and elongation rate was in 25.6-33%, which could meet the requirements for industries. Corrosion tests were conducted according to A and B methods of ASTM G28 standard, corrosion resistance of composite plate after 560°C, 580°C and 600°C heat treatment exhibited a small difference with supplied C-276 alloy. Microstructure of composite plate after 580°C heat treatment exhibited a single austenite without intermediate phase and after 650°C heat treatment with small amounts of intermediate phase. The optimal heat treatment process for the C-276/Q235-B bimetallic composite plate was air cooling after 4 h heat treatment at 580°C.