Pretreatment is important for achieving high-value utilization of biomass. This study is conducted to evaluate the destruction of the Moso bamboo cell wall via hydrothermal pretreatment at different temperatures and pH values. Compositional and morphological analyses and subsequent enzymatic hydrolysis of the solid fractions indicate that the destruction of the cell wall, instead of the degradation or removal of hemicellulose and lignin, or the configuration transition of the cellulose crystal structure, is the most critical aspect for improving bioconversion efficiency. Although only an 8%-10% weight loss is incurred and similar crystalline indexes are achieved after mild hydrothermal treatments, the recovery of glucose is doubled, whereas the recovery of xylose from pretreated samples is approximately 35%.