Abstract: According to the concept of neutral reaction and browning reaction, suggestion on casing was proposed theoretically from characteristics of burley tobacco chemical composition.Reducing sugar, acid, alkali, reducing sugar +acid, and reducing sugar +alkali could be used as casing meterial.These casing materials could take part in or catalyze reactions in burley tobacco during processing, such as neutral reaction and browing reaction.The result of preliminary experiment showed that reducing sugar+acid and reducing sugar+alkali had functions for alleviating stimulation, reducing offensive odor, and improving taste of burley tobacco, and casing effect of reducing sugar+alkali was better than reducing sugar+acid.