Lignocellulosic biomass is a very important renewable resource that can be used to produce biofuels and various platform chemicals. The conversion of biomass to reducing sugars is an important intermediate step that can impact the economic benefits of the process. Modified carbon-based solid acid is a novel catalyst used in the hydrolysis process of lignocellulosic materials. The catalyst material was prepared through the incomplete carbonization and subsequent sulfonation of a mixture of glucose and p-toluenesulfonic acid, followed by oxidation using 30% H2O2 to promote the acidity. The hydrolysis efficiency of the solid acid catalyst thus prepared was considerably increased. The effects of the carbonization temperature, time, and the glucose/p-toluene-sulfonic acid ratio on catalytic efficiency were investigated in this study. Under the appropriate preparation conditions, the catalyst could hydrolyze corncob to produce 78% xylose. The activity of the catalyst slightly declined after five cycles of application.