The invention discloses an aerosolizable botulinum toxin type A AHc subunit vaccine dry powder inhalant. The AHc subunit vaccine dry powder is successfully prepared by a spray freeze drying method. The mass median aerodynamic diameter (MMAD) is close to 2.5 [mu]m. The particles are spherical, and loose and porous in shape, and the distribution of particle size is uniform. The particle size of therange is beneficial to the deposition of the vaccine to the deep part of the lung, the contact reaction time between the antigen and the mucosa tissue is increased, and the immune protection effect isimproved. The recombinant AHc subunit vaccine dry powder prepared by the invention meets the requirements of lung delivery immunity, can protect mice against 1440 times LD<50> BoNT/ A complex attackthrough lung delivery immunity, lays a foundation for the development of botulinum toxin subunit vaccine dry powder vaccine and the research of lung delivery immunity protection effect, and provides an advanced technical scheme for the development of inhalation dry powder vaccine.