TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Method: The process of performing steam explosion pretreatment on shell of shiny leaved yellowhorn by using steam explosion method to break the structures of lignin, cellulose, hemicellulose and other cross-linked high molecular structures, specifically to degrade the hemicellulose structure to lower the content of xylooligosaccharide, which sets foundation for effectively converting polysaccharide into methane. The shiny leaved yellowhorn shell, which is reprocessed by steam explosion is processed by microorganism acidification and methanation to generate biological natural gas. The lignin is further extracted from the residue obtained from performing steam explosion pretreatment on shell of shiny leaved yellowhorn, for preparing biological natural gas. The enzymatic hydrolysis lignin refers to residue for preparing biological natural gas, biological ethanol or functional polysaccharide by taking material for performing microorganism enzymatic hydrolysis on the biomass or biomass directly processed by biological enzyme catalyst as raw material. The enzymatic hydrolysis lignin is extracted by strewing organic solvent or thin alkaline aqueous solution to dissolve the lignin and turn into a liquid phase, and during the gasifying process, most celluloses fail to be converted and little lignin remains in the solid residue. The saccharide in the solid residue obtained from performing steam explosion pretreatment on shell of shiny leaved yellowhorn, is converted into natural gas and is separated, and extracted lignin is enzymatically hydrolyzed, thus the residual cellulose in the residue is further enzymatically hydrolyzed to convert into biological ethanol. The method comprises (i) pre-grinding the shiny leaved yellowhorn shell into fragment with diameter less than 1 cm by a grinding machine, (ii) performing steam explosion to remove the pulp from the material by a steam explosion experimental device under 1-3.5 MPa for 60-180 seconds, depending on the requirement, performing the second time or multiple times of steam explosion on the material, (iii) adding water, which is 3-5 times as that of the material, stirring for 10-15 minutes, feeding into an acidification tank, converting partial saccharide into acid under the functions of air and microorganism, feeding the material into an anaerobic methane converting tank, when the pH is decreased to 4.2-5.2, preserving at 35-37 degrees C to obtain biological natural gas, filtering the residue of gasified material, performing acidification and methanation on the filtrate once again, and applying the solid filter slag for extraction of enzymatic hydrolysis of lignin, (iv) mixing the solid filter slag by using thin alkaline liquid (1-5%) or organic solvent (1-5%), heating for 60-120 minutes at 65-150 degrees C, filtering to obtain filtrate, which is lignin solution obtained from the extraction, regulating pH of the filtrate to 2.5-3 by a thin acidic solution (1-5%), separating the lignin deposit, filtering and drying to obtain lignin, (v) rinsing the solid filter slag after extracting lignin till it is neutral, enzymatically hydrolyzing by using cellulase to obtain biological ethanol, and (vi) using the residue obtained after preparing biological ethanol as fertilizer of flue of boiler.