Method for preparing ethanol from banana trees

The invention discloses a method for preparing ethanol from banana trees. The method comprises the following steps: collecting the banana trees, mechanically dehydrating the banana trees, crushing the dehydrated banana trees, carrying out pressure maintaining boiling, and carrying out steam explosion; preparing a banana tree powder slurry mash, adjusting the pH value of the mash, and carrying out lignocellulose enzyme hydrolysis to form sugar; adjusting the pH value of the sugar, adding 15-25% of yeast mash, and carrying out continuous fermentation to form finished yeast mash; and boiling the finished yeast mash, condensing the boiled finished yeast mash to obtain an alcohol-containing liquid, and distilling the alcohol-containing liquid at 78.3 DEG C to obtain ethanol with the purity being 99% or more. The ethanol is prepared from the banana trees in order to make agriculture and forestry wastes become industrial product raw materials, and the optimum substrate content and optimum cellulase are determined th