Abstract: The improvement in thermal deformation resistance of the copper stave in the bosh area and lower stack area of a blast furnace is the key factor for prolonging the blast furnace campaign life. The heat transfer performance and thermal deformation of the copper-steel composite stave at the bosh area and lower stack area were investigated by thermal testing and numerical simulation,and compared with those of the copper stave. The results show that the maximum temperature on the rib hot surface of the copper-steel composite stave without skull is 180℃ when the gas temperature is 1200℃,and approaches to the heat transfer performance of the copper stave. The maximum equivalent stress of the copper/steel interface is about 114.45 MPa,lower than the tensile strength of the copper-steel plate. The copper-steel composite stave subjects to bending deformation,and the center displacement in the z direction is 0.66 mm,about 25.8% lower than that of the copper stave. The up/down displacement in the z direction is 0.13 mm,about 50%lower than that of the copper stave. The curvature is 0.93×10^-4 mm^-1,about 51.81% lower than that of the copper stave. The thermal deformation resistance of the copper-steel composite stave is superior to that of the copper stave,and it can overcome the fracture of bolts and pipes in the copper stave due to excessive thermal deformation.