NOVELTY - Device for preparing reducing sugar by enzymolysis of bagasse comprises one enzyme membrane reactor containing one reaction liner for holding bagasse and cellulose buffer solution to process enzymatic hydrolysis; one water bath container; one separating unit containing one membrane component adapted to the reactor; one enzyme transferring device for re-absorbing the enzyme to make the enzymolysis residua and new bagasse contact completely; and linking pipelines, valves and pumps between each unit.    USE - As a device for preparing reducing sugar by enzymolysis of bagasse (claimed).    ADVANTAGE - The devices improves the enzymolysis efficiency. In the method, the step of enzyme re-absorbing new substrate achieves the cyclic utilization of enzyme and lowers the cost of enzymolysis.    DETAILED DESCRIPTION - Device for preparing reducing sugar by enzymolysis of bagasse comprises one enzyme membrane reactor containing one reaction liner for holding bagasse and cellulose buffer solution to process enzymatic hydrolysis; one water bath container for providing thermostatic water bath for the reaction liner; one separating unit containing one membrane component adapted to the reactor for separating enzymatic hydrolysate of the enzymatic hydrolysis to obtain reducing sugar and enzymolysis residua; one enzyme transferring device for re-absorbing the enzyme to make the enzymolysis residua and new bagasse contact completely, where the new reaction material is made by transferring enzyme re-absorbed new bagasse transferred from the pipeline to the reaction liner of enzyme membrane reactor to complete the enzymatic hydrolysis; and linking pipelines, valves and pumps between each unit. An INDEPENDENT CLAIM is included for preparing reducing sugar by enzymolysis of bagasse involving pre-treating raw material bagasse, crushing into 5-50 meshes, processing pre-treating; processing enzymatic hydrolysis, processing enzymatic hydrolysis on the pre-treated bagasse and cellulose buffer solution in enzyme membrane reactor, separating the enzymolysis product in enzyme membrane reactor by membrane device to obtaining reducing sugar; transferring and re-absorbing by loading the enzymolysis residua after separating reducing sugar to the enzyme transferring device, adding in new buffer solution and new bagasse to process re-absorbing to form new reactant; recycling enzyme, transferring the new reactant to the reaction liner of enzyme membrane reactor through pipeline to process next round of enzymatic hydrolysis, abandoning the old residue after separation.