Abstract: Effects of reaction parameters, including the solvent ratio, liquefaction duration, temperature, catalyst dosage, ratio of cornstarch and the solvent on the liquefaction of cornstarch in polyhydric alcohols and its liquefied products were studied by means of singlefactor experiment method. The results showed that sulfuric acid was an effective catalyst to the liquefaction of cornstarch in polyhydric alcohols. The optimal liquefaction technology included: ratio of cornstarch to solvent (mixture of PEG 400 and glycerin) was 1∶6 (w/w); dosage of sulfuric acid was 3% of the solvent; ratio of PEG 400 to glycerin in the solvent was 7∶3 (w/w); the reaction time was 25 min, and the reaction temperature was 150℃, respectively. The residue percentage was 2.0% and the liquefied product was 447.0 mg KOH/g under the optimal liquefaction conditions.