The invention discloses a method for pretreating lignocellulose by using a renewable ionic liquid aqueous solution, including the steps of: (1) taking a choline and amino acid ionic liquid aqueous solution as a pretreatment solvent, mixing lignocellulose and the pretreatment solvent under the protection of nitrogen, stirring at 50-120 DEG C, cooling to room temperature, filtering, washing residue, and drying to obtain the pretreated lignocellulose; and (2) weighing the pretreated lignocelluloses, adding a citrate buffer, adding cellulase, reacting for 3-12 h with 150-250 r / min at 40-60 DEG C to obtain sugar liquid mainly including glucose and xylose. The pretreatment process not only can effectively enhance the efficiency of enzymatic hydrolysis of lignocelluloses, and improve the yield of fermentable reducing sugar, but also has the advantages of environmental protection, renewability, low viscosity, easy operation, low cost, and low power consumption.