A device for performing continuous carbonation and impurity removal for xylose mother liquor, comprising an alkali addition unit, a continuous carbonating unit, a discharge controlling unit, a CO 2 supply station, a vapor station and an after-carbonation tank, wherein the alkali addition unit is configured to add Ca 2 alkaline liquid into xylose mother liquor, the continuous carbonating unit is configured to introduce CO 2 supplied from the CO 2 supply station into the alkali-added xylose mother liquor to perform carbonation and mixing so as to remove impurities such as colloids and pigments in xylose mother liquor, the discharge controlling unit is configured to introduce the CO 2 supplied from the CO 2 supply station and vapor transported from the vapor station into the carbonated xylose mother liquor so as to control and stabilize a pH value of the carbonated xylose mother liquor, and the after-carbonation tank is configured to collect and temporarily store the carbonated and impurity-removed xylose mother liquor so as to prepare for a next procedure, characterized in that the discharge controlling unit comprises a discharge carbonation tank, a variable-frequency mixer, a tank temperature sensor, a tank temperature controller, a CO 2 inlet flow controller, a CO 2 inlet regulating valve, a discharge pH sensor, a discharge pH controller, a vapor regulating valve and a discharge switching valve, the discharge carbonation tank collects the carbonated xylose mother liquor transported from the continuous carbonating unit, the CO 2 in the CO 2 supply station flows through the CO 2 inlet flow controller and then enters the discharge carbonation tank, the vapor station introduces vapor into the discharge carbonation tank through the vapor regulating valve, the after-carbonation tank stores the processed xylose mother liquor flowing through the discharge switching valve, the variable-frequency mixer mixes xylose mother liquor in the discharge carbonation tank, the tank temperature sensor monitors a temperature of the discharge carbonation tank, the discharge pH sensor monitors a discharge pH value of xylose mother liquor, the variable-frequency mixer, the tank temperature controller, the discharge pH controller and the vapor regulating valve are interlocked with each other, the tank temperature controller regulates an opening degree of the vapor regulating valve according to the discharge pH value and controls the variable-frequency mixer at the same time, the variable-frequency mixer, the CO 2 inlet flow controller, the CO 2 inlet regulating valve and the discharge pH controller are interlocked with each other, and the discharge pH controller controls a flow rate of the CO 2 output by the CO 2 supply station to the discharge carbonation tank based on the discharge pH value and controls the variable-frequency mixer at the same time. wherein the alkali addition unit is configured to add Ca 2 alkaline liquid into xylose mother liquor, the continuous carbonating unit is configured to introduce CO 2 supplied from the CO 2 supply station into the alkali-added xylose mother liquor to perform carbonation and mixing so as to remove impurities such as colloids and pigments in xylose mother liquor, the discharge controlling unit is configured to introduce the CO 2 supplied from the CO 2 supply station and vapor transported from the vapor station into the carbonated xylose mother liquor so as to control and stabilize a pH value of the carbonated xylose mother liquor, and the after-carbonation tank is configured to collect and temporarily store the carbonated and impurity-removed xylose mother liquor so as to prepare for a next procedure, characterized in that the discharge controlling unit comprises a discharge carbonation tank, a variable-frequency mixer, a tank temperature sensor, a tank temperature controller, a CO 2 inlet flow controller, a CO 2 inlet regulating valve, a discharge pH sensor, a discharge pH controller, a vapor regulating valve and a discharge switching valve, the discharge carbonation tank collects the carbonated xylose mother liquor transported from the continuous carbonating unit, the CO 2 in the CO 2 supply station flows through the CO 2 inlet flow controller and then enters the discharge carbonation tank, the vapor station introduces vapor into the discharge carbonation tank through the vapor regulating valve, the after-carbonation tank stores the processed xylose mother liquor flowing through the discharge switching valve, the variable-frequency mixer mixes xylose mother liquor in the discharge carbonation tank, the tank temperature sensor monitors a temperature of the discharge carbonation tank, the discharge pH sensor monitors a discharge pH value of xylose mother liquor, the variable-frequency mixer, the tank temperature controller, the discharge pH controller and the vapor regulating valve are interlocked with each other, the tank temperature controller regulates an opening degree of the vapor regulating valve according to the discharge pH value and controls the variable-frequency mixer at the same time, the variable-frequency mixer, the CO 2 inlet flow controller, the CO 2 inlet regulating valve and the discharge pH controller are interlocked with each other, and the discharge pH controller controls a flow rate of the CO 2 output by the CO 2 supply station to the discharge carbonation tank based on the discharge pH value and controls the variable-frequency mixer at the same time.