NOVELTY - Preparing saccharification solution involves (a) pre-processing substrate mixture, (b) obtaining saccharified preprocessed material, (c) carrying out saccharification process of substrate (A), and generating oligosaccharide by adding a heat resistant xylanase to preprocessed material to obtain substrate (A), and saccharogenic amylase mixture, and (d) carrying out saccharification process of substrate (A), and oligosaccharide, and generating a monosaccharide by adding heat resistant beta -xylosidase to substrate (A), and saccharogenic amylase mixture.    USE - The method is useful for preparing saccharification solution (claimed).    ADVANTAGE - The method provides high yield of xylose.    DETAILED DESCRIPTION - Preparing saccharification solution involves (a) pre-processing substrate mixture which is formed by mixing aqueous ammonia with lignocellulosic biomass as a substrate, and maintaining the mixture at a predetermined temperature, for predetermined time, (b) obtaining saccharified preprocessed material by vaporizing ammonia and separating ammonia, (c) carrying out saccharification process of at least one part of substrate (A), and generating oligosaccharide by adding a heat resistant xylanase to the saccharified preprocessed material to obtain substrate (A), and saccharogenic amylase mixture, where the preprocessed material is added with a heat resistant beta -xylosidase when the material placed in a first temperature range descends to the temperature which can disregard saccharification inhibition reaction, and (d) carrying out saccharification process of the substrate (A), and the oligosaccharide, and generating a monosaccharide by adding the heat resistant beta -xylosidase to the substrate (A), and saccharogenic amylase mixture to obtain substrate (B), and saccharogenic amylase mixture, where beta -xylosidase is added when the substrate (A) and saccharogenic amylase mixture placed in second temperature range descends to the temperature which can disregard saccharification inhibition reaction.