NOVELTY - Liquefying device for acid hydrolysis of lignocellulosic materials comprises a pan and a second thermometer installed in the upper part of an inner cavity of a reaction container. The lower part is equipped with a heater. A stirring rod is inserted from the top of the reaction container. The upper end of the stirring rod is connected with a motor. The lower end of the stirring rod is connected with an electric machine equipped with a speed regulating device. The stirring rod at the periphery is distributed with a condenser, a first thermometer and a material outlet.    USE - The liquefying device is useful for the acid hydrolysis of the lignocellulosic materials.    ADVANTAGE - The liquefying device liquefies the lignocellulosic materials without high pressure and high temperature; ensures low material consumption; and has simple structure.    DETAILED DESCRIPTION - Liquefying device for acid hydrolysis of lignocellulosic materials comprises a pan and a second thermometer installed in the upper part of an inner cavity of a reaction container. The lower part is equipped with a heater. A stirring rod is inserted from the top of the reaction container into the reaction container. The upper end of the stirring rod is connected with a motor. The lower end of the stirring rod is electrically connected with an electric machine equipped with a speed regulating device. The stirring rod at the periphery is distributed with a condenser, a first thermometer and a material outlet. The condenser of a lower port is connected with the reaction container. An internal snake-shaped cooling water pipe is respectively connected with two ends of a water inlet pipe. The first thermometer measures temperature of the reaction container. The second thermometer measures the temperature at one end of the pan, which is lower than that of the heat conducting oil surface, and the other end is electrically connected with a temperature controller.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic representation of the liquefying device.