In this paper, the pulping process of wheat straw in the acidic ionic liquid N - methyl imidazole hydrosulfate is analyzed. The pulp yields can be stabilized at about 50% under the optimum process conditions by 3 times repetitive verification experiments. The boiling solvent ionic liquid can be recycled repeatedly, and its average recovery is 89.2%. Effects of cooking temperature and time on delignification and the lignin structure change are discussed by the infrared examines during the pulping process. XRD diffraction analysis of cooked wheat straw pulp fibers indicates that the cooking process is mild without causing damage to the cellulose. Delignification reaction kinetics of the ionic liquid N - methyl imidazole hydrosulfate cooking wheat straw pulping has been carried on preliminary discussion.