NOVELTY - A comprehensive utilization of lignocellulosic biomass involves (a1) performing n-stage acid hydrolysis of lignocellulosic biomass to obtain acid hydrolysis residue; (b1) treating the residue by alkali solution to extract alkali lignin; (c1) processing resultant residue with cellulose to carry out enzymolysis and obtaining glucose solution and enzymolysis residue; and (d1) returning enzymolysis residue in step (b1) or combining enzymolysis residue with new acid hydrolysis residue solution, and then through steps (c1) and (d1) extracting lignin and enzymatic hydrolysis of cellulose.    USE - As comprehensive utilization method of lignocellulosic biomass (claimed).    ADVANTAGE - The present method realizes maximized use of lignocellulosic biomass source; and uses acid hydrolysis, and then alkali hydrolysis and enzymolysis, finally the cellulose, hemicellulose to alternately process route of the extraction process. In which process lignocellulosic biomass to obtain a hydrolysis liquid to a separating, condensing and thus improve the purity of the alkali lignin, which is good for using lignin producing the products with high added value. The present method reduces the ash in the alkali lignin solution and residual alkali solid content, which is more beneficial for using lignin to produce the products with high added value; is eco-friendly; and utilizes low alkaline solution treatment temperature (40-100 degrees C) to extract the lignin, thus reduces lignin damage.    DETAILED DESCRIPTION - A comprehensive utilization method of lignocellulosic biomass involves: (a1) adding freshly prepared acid solution into a first acid hydrolysis reaction kettle containing lignocellulosic biomass to begin n grade acid hydrolysis of the biomass, discharging the first level acid concentration of the acid solution from the reaction kettle, then adding water in second level hydrolyzing reaction kettle, discharging second grade acid hydrolysis of the acid solution from the reaction kettle, then adding water in a third level hydrolyzing reaction kettle, discharging acid until adjusting acid for n times, followed by adding into the first acid n-stage hydrolysis reaction kettle, discharging the acid solution as the final pentose solution in first level hydrolyzing reaction kettle for acid hydrolysis residue, and in new wood cellulose biomass raw material, and circulating lignocellulosic biomass by continuous hydrolysis, where the concentration of the acid solution from the first level to the 'n'th level gradually reducing the amplitude as the first stage utilizes a solution at a concentration of 10-40%, n is greater than or equal to 2; (b1) treating the acid hydrolysis residue by alkali solution, so as to extract the alkali lignin; (c1) processing obtained hydrolysis residue with cellulose to carry out enzymolysis and obtaining glucose solution and enzymolysis residue; and c(d1) returning enzymolysis residue in step (c1) or combining the enzymolysis residue with new acid hydrolysis residue solution, and then through steps (c1) and (d1) extracting lignin and enzymatic hydrolysis of cellulose.