The invention discloses a method for improving the bagasse combustion calorific value. The method comprises the operation steps that 1, before bagasse is fed into a feeder, bagasse is crushed and screened, and the size of crushed bagasse granules is controlled to be smaller than 3mm; 2, hot air pipes communicate with the two sides of a falling pipe on the lower portion of the feeder in a tripod mode, and hot air is introduced into the falling pipe to be mixed with the bagasse granules fed into the feeder; and 3, the bagasse granules and the hot air mixed in the step 2 are injected into a hearth of a boiler through a fuel nozzle. The hot air in the step 2 is formed by mixing high-temperature flue gas extracted from the hearth of the boiler and hot air of an air preheater, and the temperature of the hot air is controlled to be from 300 DEG C to 350 DEG C. By means of the method, the temperature of the hearth of the bagasse boiler can be improved, the heat efficiency of the boiler can beimproved, the amount of steam produced by one ton of bagasse is improved, and emission of boiler flue gas nitrogen oxide is reduced.