The invention discloses a biomass fuel crusher. The biomass fuel crusher comprises a supporting base, wherein a rack is arranged on the supporting base, a feeding bin is arranged at the front part of the rack, a crawler-type feeding conveyer is horizontally distributed in the feeding bin, a forced feeding roll is arranged at the top part of the rear end of the crawler-type feeding conveyer, a crushing compartment is arranged on the rack at the rear part of the forced feeding roll, a crushing roll is arranged in the crushing compartment, a crushing cutter bit is arranged on the surface of the crushing roll, a crushing separating screen is coaxially sheathed at the periphery of the crushing roll, a crushing feeding hole matched with the forced feeding roll is formed at the front part of the crushing separating screen, a discharging compartment communicated with the crushing compartment is arranged at the bottom of the crushing compartment, a discharging hole is formed at the bottom of the discharging compartment, and a discharging conveyer is arranged under the discharging hole. According to the biomass fuel crusher, the universality of the crusher is improved, various biomass fuels in wastes in the fields of agriculture, forest industry, industry, construction industry and the like can be subjected to crushing processing, the operating efficiency and the crushing quality of the crusher are improved, the service life of the crusher is prolonged, the power consumption is reduced, and the using cost and the operating expense are reduced.