Lignocellulosic constituents as renewable feedstock can be utilized for various applications. A systematic procedure for separation of cellulose and lignin followed by hydrolysis of hemicelluloses was proposed in this study. Sugarcane bagasse was first subjected to alkaline hydrolysis to remove lignin and hemicelluloses. Then cellulose was separated from the alkali pretreatment residue and further purified. Meanwhile, the obtained pre-hydrolysis liquor (PHL) was acidified to precipitate lignin, and the filtrate was hydrolyzed with 1-methylimidazolium hydrogen sulfate ([Hmim]HSO4) to prepare furfural. Response surface methodology (RSM) was employed to determine optimal conditions for isolation of cellulose. The sequential treatments resulted in a total release of over 77.3% of the original cellulose and 84.5% of the original lignin. In particular, 7.5% yield of furfural was obtained. The structures of the isolated cellulose and lignin were elucidated with Fourier transform infrared spectroscopy (FT-IR).