The OH absorption bands of boehmite on the infrared spectra obtained at the various temperatures were deconvoluted by the simplex method of computer program. The deconvoluted bands of boehmite corresponded to five specific OH groups appeared to have band maxima at 2,700∼2,720 ㎝^-1（band 1）, 2,906-2,914 ㎝^-1(band 2), 3,064-3,072㎝^-1(band 3), 3,255-3,269㎝^-1(band 4), 3,417㎝^-1(band 5). The band 1 and 2 were assigned to the symmetric and asymmetric stretching vibrations of hydroxy1 groups of hydrated aluminum cations. The absorption of band 3 and 4 were assigned to the structural hydroxyls located between the alumina layers. And the band 5 was assigned to the single OH attached to the aluminum.