Abstract: In this paper, corncob was used as feedstock and toluene was selected as extraction solvent. The objective of this work was to study the furfural yields by hydrolysis of corncob with different sulfuric acid concentrations at various liquid/solid ratios under the atmospheric pressure. Four important parameters consisting of heating temperature (140-190℃), reaction time (20-120 min), mass fraction of sulfuric acid (5%-35%, mass fraction) and liquid/solid ratio were evaluated. The conversions of corncob and furfural yield were found to increase significantly with the heating temperature and reaction time increasing. When the heating temperature was 160℃,the maximum furfural yield, i.e. 8.43% was obtained within 90 min. The concentration of sulfuric acid was found to affect the furfural yield. The optimal furfural yield was observed when the sulfuric acid concentration was 25%. After this, as the sulfuric acid concentration increased, the furfural production decreased. When the concentration was up to 35%, the furfural yield was only 0.62% at 90min. By analysis of experimental results, the optimal parameters of furfural prepared as follows: the optimum heating temperature 160℃, the appropriate reaction time 60 min, the best acid concentration 25% and the best ratio of liquid to solid 10. Under these conditions, a furfural yield of 8.15% was obtained.