The invention provides a mesoporous-microporous carbon nanotube-montmorillonite composite aerogel material and a preparation method thereof. The preparation method comprises the following steps: respectively preparing wet gel of carbon nanotube-loaded dexamethasone and wet gel of montmorillonoid, and mixing the wet gel of carbon nanotube-loaded dexamethasone, the wet gel of montmorillonoid with agentamicin solution to prepare the mesopores-microporous carbon nanotube-montmorillonite composite aerogel material. With the gradual increase of the soaking time, gentamicin loaded in mesopores is released first, and with the further increase of the soaking time, dexamethasone loaded in micropores is subsequently released, so that the effects of one-time drug taking and multi-time drug administration are achieved.