To prevent unscheduled trip of power plants by boiler tube damage, it is important to monitor boiler tube temperature during power plant operation. However, the direct measurement of tube temperature in the boiler is impossible by installing temperature probe during power plant operation because of harsh condition such as high temperature in the boiler heating zone. In this study, methodology to predict the tube temperature in the boiler heating zone is suggested using measured tube temperature in boiler none-heating zone. For precise local maximum tube temperature, the flue gas condition is considered.