The invention discloses a method for preparing an expanded microcrystal graphite material from microcrystal graphite, which comprises the following steps: 1) crushing and milling a microcrystal graphite raw material to obtain microcrystal graphite powder; 2) mixing the obtained microcrystal graphite powder with an intercalator and a strong oxidizer to perform chemical intercalation treatment so as to obtain an expandable microcrystal graphite acidic suspension, filtering, washing, and drying to obtain expandable microcrystal graphite; and 3) carrying out heating roasting treatment on the obtained expandable microcrystal graphite in an atmosphere furnace to obtain the expanded microcrystal graphite material. The invention provides new application of the microcrystal graphite; the obtained expanded microcrystal graphite material is vermian and porous, and the expanded ratio is 100-200 times; and the expanded microcrystal graphite material has the advantages of large specific area, high porosity, favorable adsorbability and the like. The microcrystal graphite raw material has abundant resources; and the technical process is short, can be used for producing the microcrystal graphene material and is beneficial to popularization and application.