The four key parameters, including reaction time, reaction temperature, the amount of corn stover charged to definite liquefying reagent, and the dosage of catalyst affect the efficiency of corn stover liquefaction were investigated. With the help of SAS software, rotational quadratic regression design and response surface analysis, the relationships among unliquefied corn stover residue and reaction time, reaction temperature, the amount of corn stover charged to definite liquefying reagent, and the dosage of catalyst were studied. The mutual interaction of the four parameters was quantificationally described. The experimental results showed that with liquefying reagent of 100g, the reaction temperature of 158℃, the reaction time of 63 min,the amount of corn stover meal charged of 17 g and the catalyst dosage of 2.7g,the liquefied products could be optimized with only 0.2% unliquefied. 