NOVELTY - Processing stalks of fiber crops (plants), preferably hemp and/or flax, comprises: preparing cellulose, ethanol and yeast by applying digesting liquor in sulfite/sulfate delignification, fermentation, and purification processes during isolating the cellulose, washing and subjecting the digesting liquor alcoholic fermentation; removing the yeasts and purifying the solution; treating the spent digesting liquor with a mixture of calcium oxide and magnesium oxide; and after separating the precipitated deposit, subjecting a clear fluid to alcoholic fermentation process.    USE - The method is useful for processing stalks of fiber crops (plants) preferably hemp and/or flax.    ADVANTAGE - The method is capable of processing stalks of fiber crops (plants) with high flexibility and quality.    DETAILED DESCRIPTION - Processing stalks of fiber crops (plants), preferably hemp and/or flax, comprises: preparing cellulose, ethanol and yeast by applying digesting liquor in sulfite or sulfate delignification, fermentation, and purification processes during isolating the cellulose, washing and subjecting the digesting liquor to alcoholic fermentation, and subjecting a broth from the distillation of ethanol to yeast fermentation; removing the yeasts and purifying the solution, where the delignification process is carried out at a temperature of 110-180 degrees C using a digesting liquor, i.e. a solution of sodium and/or potassium bisulfate (IV) or a solution of sodium and/or potassium bisulfate (VI) having a pH value of 1-13.5, where the content of magnesium (Mg+2) is 0.01-0.03% (mass fraction), and the delignification process continues until the content of soluble carbohydrates in the digesting liquor is above 30% (mass fraction); after isolating the cellulose, treating the spent digesting liquor (20-70 kg per 1 m3) with a mixture of calcium oxide and magnesium oxide (30-70% (mass fraction)); and after separating the precipitated deposit, subjecting a clear fluid to alcoholic fermentation process, burning the deposit, and returning the obtained combustion gases to the delignification process, and returning the ash in order to be utilized in the purification of the spent digesting liquor and as a supplementary source of calcium (Ca+2 and) Mg+2 ions in the fresh digesting liquor.