NOVELTY - Converting herbaceous plant fiber into fuel alcohol involves grinding raw materials; adding carbon dioxide and applying supersonic waves; adding liquid mixture of alcohol, liquid ammonia and water; adding dilute sodium hydroxide; boiling mixture for 20 minutes to 2 hours at 100-250 degrees C; adding at 40-60 degrees C and pH of 3-6, an aqueous suspension of cellulase having endo- beta -glucanase, exo- beta -glucanase and 3-glucanase, then adding suspension of Candida mycoderma, Rhizopus oryzae and dry yeast; and keeping the temperature at 30-40 degrees C for 50-80 hrs.    USE - For converting herbaceous plant fibers into fuel alcohol (claimed).    ADVANTAGE - The method has extensive sources of raw material; is simple process; has low cost with low energy consumption; has high output rate; has environment protection and partial replacement of oil; and converts herbaceous plant fibers into other chemical products and biochemical products.    DETAILED DESCRIPTION - Converting herbaceous plant fibers into fuel alcohol involves grinding raw materials of herbaceous plants to the size of 100-180 Mesh, and loading them in a reaction tank; adding carbon dioxide (CO2) and applying supersonic waves; adding a liquid mixture of alcohol: liquid ammonia: water in a ratio of 30-40%:6-10%:50-64% by weight to the raw material in a proportion of 1:1.5-1:3 of the raw materials to the liquid mixture by weight; adding dilute alkali NaOH in a proportion of 3-12% of alkali to the raw materials by weight, and stir the mixture; boiling the mixture for 20 minutes to 2 hours under the temperature of 100-250 degrees C and the pressure of 2-6 MPa; reducing the pressure to normal atmospheric pressure and reducing the temperature to 30-40 degrees C; optionally, recovering the organic liquids; under the temperature of 40-60 degrees C and pH of 3-6, adding aqueous suspension of cellulase comprising endo- beta -glucanase, exo- beta -glucanase and 3-glucanase which account for 0.5-3% of the liquid weight, and allowing a reaction to take place for 8-12 hours; and under the temperature of 40-60 degrees C and pH of 3-6, adding aqueous suspension of Candida mycoderma, Rhizopus oryzae and dry yeast which account for 3-8% of the liquid weight; optionally further adding ammonium sulfate and phosphoric acid; and keeping the temperature at 30-40 degrees C and allowing reaction to take place for 50-80 hours.