For the problem of overheating caused by unevenly heating of high-temperature heating surfaces along the width direction in large coal-fired boilers, a detail study have been performed on the final superheater of 600 MW supercritical coal-fired boiler. Based on the prediction of oxide scale growth model and the heat deviation calculation, the influence of the oxide scale growth on tube temperature was analyzed. Results show that the tube temperature increases with the growth of oxide scale, which would lead to local temperature over-run of the superheater tube and decline of creep rupture life, thus the effect of oxide scale on tube temperature should be considered in the heat deviation calculation.