As an "upstream" process in biorefinery, biomass dismantling can dismantle the natural stable structure of lignocellulosic biomass and separate its three major components. To increase the value of the entire biomass by fully utilizing the three main components (cellulose, lignin, and hemicellulose), this study proposes a two-step decomposition system combining formic acid (FA) pretreatment and ethylene glycol-NaOH (EGA) dismantling, aiming to effectively convert sugarcane bagasse into xylose, fermentable glucose, and high-value lignin. In the first step, FA pretreatment removed 79.85 % of hemicellulose at 140 °C for 90 min with 3 % FA. Based on the first step, further combination of EGA dismantling can achieve a hemicellulose removal rate of 92.05 % and a lignin removal rate of 95.90 %. In addition, the solid residue was hydrolyzed by enzymes, and the glucose conversion rate was close to 83.29 % when the cellulase dosage was 10 FPU/g. In addition, the lignin recovered by this system retained 83.62 % of the natural β-O-4 structure, which has the potential to catalyze the formation of aromatic monomers. In summary, this gentle two-step system simultaneously improves the efficiency of lignocellulose decomposition and produces different value-added products, demonstrating the potential for industrial-scale production.