In order to hydrolyze the corncob hemicellulose fully, response surface methodology (RSM) was applied to optimize the hydrolysis condition of corncob hemicellulose. Judged by the xylose weight obtained from per gram dry corncob as hydrolysate standard, the impact of hydrolysis temperature, hydrolysis time and concentration of H2SO4 were studied. When the material and liquid ratio was 1:10, the optimum hydrolysis condition were hydrolysis temperature 119.8℃, hydrolysis time 1.5 h, and 1.16% concentration of H2SO4 (v/v). Under this hydrolysis condition, 0.31 g xylose was obtained from per gram dry corncob. The optimized hydrolysis condition of corncob hemicellulose raised the yield of xylose and laid a foundation to hydrolyze the corncob hemicellulose fully, which had important application value.