NOVELTY - Immobilizing beta -glucosidase and coordinating with cellulose to hydrolyze straw cellulose, comprises: (a) using chitosan, propionic acid, polyethylene glycol (PEG)400 and iron oxide (Fe2O3) particle to prepare magnetic chitosan microsphere; (b) absorbing beta -glucosidase on the chitosan magnetic microsphere immobilized carrier to obtain magnetic immobilized beta -glucosidase; and (c) using the magnetic immobilized beta -glucosidase to coordinate with cellulose to hydrolyze straw cellulose.    USE - The method is useful for immobilizing beta -glucosidase and coordinating with cellulose to hydrolyze straw cellulose (claimed).    ADVANTAGE - The immobilized enzyme prepared by the method has homogeneous shape, great specific surface area, high machine strength and high enzyme activity. It can be recycled easily. The enzyme is capable of coordinating with the cellulose to hydrolyze straw cellulose, and increasing the yield of the hydrolyzed sugar. The stability for using repeatedly is good. The enzyme is capable of reducing the cost for hydrolyzing straw cellulose via the enzyme method.    DETAILED DESCRIPTION - Immobilizing beta -glucosidase and coordinating with cellulose to hydrolyze straw cellulose, comprises: (a) using chitosan, propionic acid, polyethylene glycol (PEG)400 and iron oxide (Fe2O3) particle to prepare magnetic chitosan microsphere, using glutaraldehyde to activate and obtain immobilized carrier, stirring components equably in 45-60 ml of ionized water system with 0.5-1.0 g of chitosan, 1.5-2.5 mass% of propionic acid, 40-60 mu l of PEG400 and 0.5-1.0 g of Fe2O3 particle to form transparent homogeneous colloid, removing bubble, dripping 50-300 ml of 2M sodium hydroxide (NaOH) solution, heating for 8-12 hours to obtain chitosan magnetic microsphere, filtering and processing the 1 g of chitosan magnetic microsphere by using 20 ml of 1.5-3.0% of glutaraldehyde solution for 2-4 hours at 25 degrees C, filtering and obtaining the immobilized carrier; (b) absorbing beta -glucosidase on the chitosan magnetic microsphere immobilized carrier to obtain magnetic immobilized beta-glucuroide, adding 0.5-0.8 g of immobilized carrier to 8-12 ml of beta -glucosidase solution with pH at 4.5-5.0 and enzyme activity of 0.6-10 cellobiase International units (CBIU)/ml, shaking for 5-15 hours at 20-25 degrees C at 150-200 revolutions per minute (r/min) to obtain magnetic immobilized beta -glucosidase and (c) using the magnetic immobilized beta -glucosidase to coordinate with cellulose to hydrolyze straw cellulose, using corn straw cellulose pre-processed by alkali as substrate, using citric acid buffering solution with pH at 4.5-5.0 to prepare 50-100 g/L of size of the corn straw cellulose, adding immobilized beta -glucosidase with dosage of 80-150 g/L size and cellulose with dosage of 10-30 fermentation broth International units (FPIU)/g straw, and hydrolyzing for 10-48 hours at 40-65 degrees C.