The invention discloses an efficiently-energy-saving hot air supply method for a belt type roasting machine and belongs to the technical field of pellet production. The method comprises the steps that the belt type roasting machine is divided into eight areas, wherein the eight areas are sequentially the air-blowing drying area, the air-drafting drying area, the preheating area, the roasting area, the heat homogenization area, the first cooling area, the second cooling area and the third cooling area; the preheating area is sequentially divided into a first preheating section and a second preheating section, and the roasting area is sequentially divided into a first roasting section, a second roasting section, a third roasting section and a fourth roasting section; hot exhaust gas generated in the second preheating section and the first roasting section is conveyed to a first cooling section; hot exhaust gas generated in the second roasting section is conveyed to the air-drafting drying area; after being gathered to a heat exchanger for heat exchange, hot exhaust gas generated in the third roasting section is conveyed to a main suction fan; and hot exhaust gas generated in the fourth roasting section and the heat homogenization area is conveyed to the preheating area. By means of the efficiently-energy-saving hot air supply method for the belt type roasting machine, according to temperature distribution of the hot exhaust gas generated in each area and the flow and temperature of the hot exhaust gas required by each area, the hot exhaust gas is reasonably distributed and utilized, and the outwards-discharging amount of the hot exhaust gas is reduced.