The invention discloses a co-fermentation preparation method for ethyl alcohol by taking corn stalk and abandoned tobacco leaves as raw material and relates to the preparation method of ethyl alcohol. The method comprises the following steps: firstly, extracting the sugar and dissolving the cellulose for the abandoned tobacco leaves, filtering and collecting the filter liquor; pre-heating the corn stalk through the water, filtering and collecting the solid phase matter, executing the simultaneous saccharification and fermentation process on the collected matters and finishing. The water pre-heating processing method is used as the pre-processing means for removing the semicellulose in the corn stalk, reducing the obstruction to the cellulose from the semicellulose and enriching the cellulose from the corn stalk; the buffer solution containing the cellulose is used for extracting the fermentable monosaccharides in the abandoned tobacco leaves and hydrolyzing the cellulose in the abandoned tobacco leaves, separating the solid from the liquid and obtaining the filter liquor containing sugar; the corn stalk pre-heated by the mixed water having visible free water and having solid-to-liquid ratio of 15 to 85 (w/w) and the abandoned tobacco leaves extracting solution are processed on simultaneous saccharification and cofermentation for preparing the ethyl alcohol of high concentration (the concentration is greater than or equal to 45g/L).