TECHNOLOGY FOCUS - BIOTECHNOLOGY - Preferred Method: In producing fuel ethanol by using Lycoris plant, the sulfuric acid concentration is 0.5%, the mass ratio between the materials and the sulfuric acid water is 1:2.5; the adding quantity of the alpha -amylase is 2wt.% of the materials; the liquefying temperature is 92 degrees C; the liquefying time is 5 hours in (c); the filtrate is regulated pH value to 6.5 with 1:1 ammonia liquor, and is concentrated in vacuum to 1.15 specific weight, then is regulated PH value to 9 with 1:1 ammonia liquor in (e); acetic ester with 4 times of concentrated solution volume is used for dynamic reflux extracting; the organic phase is reserved for producing the alkaloid; the water phase is regulated PH value to 5.4 with 1:1 hydrochloric acid liquor, then is concentrated to 1/4 of the original volume in (f); the adding weight of the assistant raw material husk is 31% of the concentrated acid regulating solution; the saccharifying temperature is 67 degrees C; pH value is 5.2; the saccharifying time is 9 hours in step (g); the adding quantity of the active yeast liquid is 3% of the saccharifying mash weight; the fermenting time is 75 hours, and the temperature is 34 degrees C in (h). The composite enzyme can be replaced by the alpha -amylase in (c); the confected components of the composite enzyme are: composite cellulose enzyme 10-20%, pectase 3-7%, protease 5-15%, debranching enzyme 5-15%, plant enzyme 5-15%, enzyme 28-72%; each gram of composite enzyme is 200.000 unit. The assistant raw material husk can be replaced by the wheat bran or some assistant materials containing starch and nitrogen source of by-products processed by some agricultural products in (g). The saccharifying enzyme can be replaced by distillers yeast in (g); the common molds for producing yeast comprise Aspergillus oryzae, Aspergillus usamii and the mutant, Aspergillus niger, Aspergillus albicans. The active yeast liquor is used the sugar water containing 5% sugar at 35-38 degrees C as the active liquid in (h); the dry yeast is added by the mass ratio of 1:25 between the dry yeast and the active liquid to stir and dissolve, and cool after 40 minutes to 35 degrees C to reserve. The L. radiate corm smash is divided into the crude smash and the fine smash in (b); the crude smash ratio of the grain size of the crude smash is 1:10-15; the fine smash ratio of the grain size of the fine smash is 1:30-1:40.