The utility model discloses an internal cooling multi-section roller shell combined type large-scale supporting roller which is characterized in that a core shaft (1) and a multi-section roller shell (2) are nested together in a hot assembly way, a cooling trough (6) and an annular communicating groove (5) are respectively processed on the outer surface of the roller body of the core shaft (1), and the cooling trough (6), the annular communicating groove (5) and the multi-section roller shell (2) sleeved on the core shaft (1) form a closed chamber; water diversion channels (4) are processed inside the both ends of the roller body of the core shaft (1), one end of each of the water diversion channels (4) is communicated with the annular communicating groove (5), and the other ends are respectively communicated with water inlet channels (3) or water outlet channels (7) at the both ends of the core shaft (1). Because the multi-section roller shell (2) can be cooled through the cooling trough processed on the surface of the core shaft (1) of the supporting roller, the relative friction between the roller shell and the roller core is greatly increased; the height of the single roller shell is reduced through the multi-section roller shell (2), and the large-scale supporting roller is suitable for the batch production or the forging production of the ring rolling machine; when the thickness of the roller shell is reduced to be abandoned, the multi-section roller shell (2) is replaced, and the roller core can be reused, thereby the production cost is reduced.