Abstract: The billet temperature dropping problem as caused by the centering process are analyzed here in the paper with two simulation，i.e.，the Stephen-Boltzmann Formula and the ANSYS Workbench. As a result，it is regarded that the theoretic calculation value is similar with that from the simulation；the billet temperature drops obviously with change of the billet diameter，i.e.，the smaller the billet diameter，the bigger the temperature drop amplitude，which means that it is particularly needed to get the centering device speeded up；the billet temperature dropping is directly proportional to the cooling time；and the billet length has little effect on the centering-caused billet temperature drop. The present development situation of the billet hot-centering device is described，and the advantages and disadvantages of the hydraulic hot-centering device and those of the flame hot-centering device are analyzed. The common-used hydraulic hot-centering device ensures good centering quality，but the operation time is rather long，and the temperature drop amplitude is rather big. The flame hot-centering device performs the centering operation at the same time the billet is being conveyed，and thus the centeringcaused temperature drop amplitude is comparatively smaller，and moreover the billet can be locally heated during the centering process，resulting in more consistent piercing of the billet，and better homogeneous wall thickness of the shell end.