Polyurethane foams were prepared from the liquefie cornstalk polyol, which was obtained by the liquefaction of cornstalk in the presence of polyhydric alcohols using sulfurice acid as catalyst. The advisable liquefaction reaction conditions were selected by investigating their influences on the properties of liquefied cornstalk poluol, taking account of the requirement for the preparation of appropriate polyurethane foams. The influences of the contents of catalysts, water, surfactant, and isocyanate on the properties of polyurethane foams were also discussed, and feasible formulations for preparing cornstalk-based polyurethane foams were proposed. The results indicated that the forms prepared from such liquefied cornstalk polyol exhibited mechanical properties and thermal properties, and could be used as heat-insulating materials. (c) 2008 Wiley Periodocals, Inc.