NOVELTY - Comprehensive utilization of lignocellulosic biomass, comprises (a) performing N-grade acid hydrolysis of lignocellulosic biomass, (b) treating acid hydrolysis residue by alkali solution to extract alkali lignin, (c) carrying out enzymatic hydrolysis of alkaline hydrolysis residues using cellulase to obtain glucose solution and enzymolysis residues, and (d) returning the enzymolysis residue to step (b) for alkali solution treatment or combining the enzymatic residue with new residue for alkali solution treatment, repeating step (c) and (d), cycling, and extracting lignin and cellulose enzyme.    USE - The method is useful for comprehensive utilization of lignocellulosic biomass (claimed).    ADVANTAGE - The method realizes the maximum resource utilization of lignocellulosic biomass.    DETAILED DESCRIPTION - Comprehensive utilization of lignocellulosic biomass, comprises (a) performing N-grade acid hydrolysis of lignocellulosic biomass, where acid hydrolysis of lignocellulosic biomass is connected to a reaction kettle as a first grade and last one as N-stage, adding freshly prepared acid solution into a first grade acid hydrolysis reaction kettle, discharging the acid solution from the first grade acid hydrolysis reaction kettle into a second grade acid hydrolysis reaction kettle, discharging the acid solution from the second grade acid hydrolysis reaction kettle into a third grade acid hydrolysis reaction kettle, following the sequence in order until the N-1 acid hydrolysis reaction kettle discharge the acid solution into the N-grade acid hydrolysis reaction kettle, discharging the acid solution from the N-grade acid hydrolysis reaction kettle as a final pentose solution, taking out the acid hydrolysis slag from the first grade acid hydrolysis reaction kettle, loading into new lignocellulosic biomass raw material, and carrying out hydrolysis reaction using the first grade acid hydrolysis reaction kettle as N-grade acid hydrolysis reaction kettle, the second grade acid hydrolysis reaction kettle as the first grade acid hydrolysis reaction kettle, the third acid hydrolysis reaction kettle as the second grade acid hydrolysis reaction kettle, and N-grade acid hydrolysis reaction kettle as the N-1 grade acid hydrolysis reaction kettle to achieve continuous hydrolysis of lignocellulosic biomass, where the first stage hydrolysis reaction time is 1-4 hours, then each stage hydrolysis reaction time is gradually reduced to 25-1.5 hours, and N is an integer of greater than or equal to 2, (b) treating the acid hydrolysis residue by alkali solution to extract alkali lignin, (c) carrying out enzymatic hydrolysis of alkaline hydrolysis residues obtained in step (b) using cellulase to obtain glucose solution and enzymolysis residues, and (d) returning the enzymolysis residue obtained in step (c) to step (b) for alkali solution treatment or combining the enzymatic residue with new residue for alkali solution treatment in step (b), repeating step (c) and (d), cycling, and extracting lignin and cellulose enzyme.