This paper deals with estimation of thermal conductivity for temperature control of an aluminum plate considering radiative heat transfer. Aiming at accurate control results, model-based control method needs true values of plant parameters. In our previous research, the nominal values of plant parameters have been used for temperature control experiment. However, for the actual environment in industrial field, physical parameters such as thermal conductivity will change. Therefore this paper reports the estimation result of thermal conductivity of aluminum plate considering radiative heat transfer through experimental data.