The invention relates to a dry powder inhalant capable of preventing mycobacterium tuberculosis from transmitting through respiratory tract, and is capable of effectively solving a medical problem that mycobacterium tuberculosis infects pulmonary tuberculosis through the respiratory tract. The method comprises the following steps of: preparing the dry powder inhalant from 9.9-80% of an isoniazide sustained release microsphere, 19.9-90% of a rifampicin sustained release microsphere and 0.1-5% of a flow aid by weight percent, uniformly mixing the isoniazide sustained release microsphere, the rifampicin sustained release microsphere and the flow aid, packaging in gelatin or plastic capsules or aluminum-plastic bubble caps, or packaging in a multi-dosage dry powder inhalation device in the form of a reservoir, so as to obtain the dry powder inhalant. The dry powder inhalant disclosed by the invention is scientific and rational in formula, easy to produce and manufacture, good in use effect, and favorable for the powder to enter into pulmonary alveoli; the medicine is transmitted to and absorbed by the pulmonary alveoli to effectively kill and inhibit mycobacterium tuberculosis in trachea, bronchia and alveoli secretion of the respiratory tract, so as to reduce the quantity of floating droplets of patients of pulmonary tuberculosis removed in the surrounding environment, and to block the transmission of the mycobacterium tuberculosis in the public environment; and therefore, the dry powder inhalant has an important meaning for preventing the pulmonary tuberculosis.