This paper deals with the fiber morphology,beating performance and papermaking performance of tobacco stem (a kind of reconstituted tobacco raw material) after the extraction with alkaline ionic liquid［MMIM］DMP by means of IR and component analysis.The results show that (1) after the extraction with ［MMIM］DMP,a small amount of honeycomb structure may occur in the epidermal tissue of tobacco stalk,and the filler among fiber cells decreases significantly,while the porosity increases; (2) as the aromatic substances and lignin in tobacco stems dissolve well in the alkaline ionic liquid,the relative content of cellulose in the raw material remarkably increases; and (3) the tobacco stem after partial delignification is of uniform fiber dispersion,good beating and papermaking performances,high tensile strength (with an increment of 35%) as well as optimized bulk and porosity parameters.