The present invention relates to a method for pretreating lignocellulose by using an acid-base mixture catalyst. The method pretreats lignocellulose, by using a mixture catalyst of an acid and a base, so as not to pass through additional neutralization steps, and carries out pretreatment and simultaneous saccharification and fermentation through an identical single reactor process, thereby having an effect of producing ethanol in an excellent production yield from lignocellulosic biomass while simplifying the total process and reducing equipment costs and total processing costs.