Abstract: For the great significance of renewable energy and chemicals providing from lignocellulosic biomass hydrolysis, the quantitative paper was chosen as the model of cellulose which was the main component of lignocellulosic biomass, and its liquid products and solid residues of the optimum experimental conditions of cellulose hydrolysis in extremely low acids were chosen as the material, sugar types of the liquid products were classified by the HPLC combined with KS-802 column, and the by-products were analyzed by GC-MS qualitatively. Simultaneously the residues were observed by SEM, combined with thermogravimetric analysis, etc. from appearance to element distribution. It is observed that the main products of cellulose hydrolysis in extremely low acids are cellotetraose, cellotriose, cellobiose, glucose and fructose. The by-products are fufural, HMF, levulinic acid and some polarity compounds including ketone, aldehyde and acids. The original shape of the residues changed thoroughly and its pyrolysis reactivity, carbon and ash content increased. Finally the reaction pathways were discussed according to the analysis results so as to provide the basis for the large-scale utilization of biomass hydrolysis.