A height-adjustable seatpost with shock absorption includes an outer tube, an inner tube, a height adjustment mechanism, and a shock absorber. The inner tube is vertically movable disposed in the outer tube and includes a head located outside the outer tube and a bottom situated inside the outer tube. The height adjustment mechanism is located inside the inner tube and is configured to drive the inner tube to move relative to the outer tube. The height adjustment mechanism includes a stopper positioned above a stop flange on an inner wall of the inner tube and can be abutted against the stop flange. The shock absorber has two ends respectively abutted against the head of the inner tube and the stopper. The above-described design of the seatpost can prevent the saddle from being raised to an unexpected height for the rider.