The invention belongs to the medicinal technical field, and provides a preparation method and a use of galangal ground part essential oil. The galangal ground part essential oil comprises the following components: 1H-imidazole, 4,5-dihydro-2-( phenmethyl), 3-cyclohexene-1-methanol, alpha, alpha, 4-trimethyl, bicyclo-[3.1.1]2-heptylene, 2,6-dimethyl-6-(4-methyl), naphthalene, 1,2,3,4,4a,4,6,8a-octahydro-7-methyl, aromadendrene, eucalyptol, fenchyl acetate, benzenepropanal, bronyl acetate, benzylacetone and bicyclo-[2.2.1] heptanes-2-acetone, based on 100% in total in terms of the total weight of the galangal ground part essential oil.