The present invention provides a sector-shaped section of a continuous casting machine for heavy reduction of a solidified terminal of a continuously cast slab and a heavy reduction method. The sector-shaped section of a continuous casting machine comprises an upper frame, a lower frame, an upper driving roller, a lower driving roller, a left driven roller set, a right driven roller set, a screw-down gear and clamping cylinders which are positioned on the sector-shaped section; the clamping cylinders are used for clamping the upper frame and the lower frame and keeping the upper frame and the lower frame at a set interval; the upper driving roller is connected with the screw-down gear; the upper driving roller is connected to the upper frame through a bearing base; the lower driving roller is connected to the lower frame through a bearing base; the left driven roller set and the right driven roller set, are respectively positioned on two sides of the driving rollers; the left driven roller set is used for clamping the cast slab before reduction; the right driven roller set is used for clamping the cast slab after reduction; and the diameter ratio of the driving rollers to the driven rollers is 1.1:1-2:1. The deformation permeability of the present invention is increased, equivalent to the deformation of one rolling pass of a two-roller mill with a relatively large roller diameter, which facilitates improvement on the looseness and segregation of the center area of the continuously cast slab.