The invention discloses a method for extracting roasted and fermented malt extract by ethanol and application thereof in tobacco, in particular a method for performing step-by-step enzymolysis on malt, fermenting the malt, roasting to increase aroma, and extracting the malt extract by the ethanol and application of the malt extract in tobacco aroma increase. The malt extract is prepared from the following steps of: spraying and soaking the malt; rolling and crushing the malt; performing step-by-step enzymolysis on the malt; fermenting the malt by using aroma-producing yeast; roasting to increase aroma; extracting by using the ethanol; performing solid-liquid separation; clarifying and filtering; and distilling and concentrating to obtain the malt extract. The malt extract is added into cut tobacco of cigarettes to increase the aroma, reduce the irritation and offensive taste, and improve the mouthfeel and aftertaste. The method has the advantages that: the technology of performing step-by-step enzymolysis on the malt, fermenting the malt, and extracting the malt extract by the ethanol is simple to operate, and the malt subjected to enzymolysis and fermentation is immediately roasted without enzyme inactivation treatment, which is more convenient. The extracted malt extract has the advantages of sweet roasting and brewing aroma, fine and smooth and rich aroma, and excellent aroma increasing effect in cigarettes.