Abstract: Aroma compounds in Bacteria fermented soybean were extracted by dry distillation.the constituents then were by GCand their structures and by MS.A total of 27 compounds were identified.The principal constituents of the volatiles were tetradecane.2,6-Di(t-butyl)-4-hydroxy-4-methyl-2,5-cyclohexadien-1-one,2,6-Di-tert-butylpuinone.Dodecanol.Pentadecane,4-Methyl-2,6-di-tert-butyphenol.Hexadecane,1-(2-Octylcyclopropyl)-1-octanone,n-Lauryl acrylate,Heptadecane,Myristic acid,Octadecane,2,6-Di-t-butyl-4-nitrophenol.Palmitoleic acid,palmitic acid,Oleic acie,Stearic acid etc.The key flavour compounds were Dodecanal,12-Hydroxy-7.alpha.-eudsm-4-en-6-one,2,-Di(t-buty)-4-hydroxy-4-methyl-2,5-cycl ohexadien-1-one,2,6-Di-tert-butylquinone,Dodecanol, 4-Methyl-2,6-di-tert-butylphenol,2-n-Butyl-5-isobutylthiophene,1-(2-Octylcyclopropyl)-1-octanone,n-Lauryl acrylate,Pentadecanal,Hexahydrofarnesyl acetone,2,6-Di-t-butyl-4-nitropheno; and 5-Dodecyldihydro-2(3H)-furanone.

Key words: Bacterial fermented soybean , Key flavour compounds , Favour , GC/MS analysis