The invention discloses a scanning stage supporting device of a scanner. The scanning stage supporting device of the scanner is characterized in that the scanning stage supporting device of the scanner comprises a supporting pin and a supporting sleeve; the supporting pin is movably arranged in the supporting sleeve; and a detachable damping spring is arranged between the supporting pin and the supporting sleeve. The scanning stage supporting device of the scanner is advantageous in that a user directly snaps a fixing disc head of the supporting sleeve into a circular hole which is preset on the bracket of the scanning stage in use, so that a locking rubber ring in a positioning annular trough is closed fastened by the inner wall of the circular hole, thereby finishing fixation of the supporting device. When a scanning stage bears a pressure, a positioning pin of the supporting pin abuts against the bottom of the scanning stage. Under the function of the damping spring, the supporting pin is inserted into the sleeve body, thereby greatly improving vibration resistance of the scanning stage and prolonging service of the scanning stage.