A height-adjustable seatpost (1) with shock absorption includes an outer tube (10), an inner tube (20), a height adjustment mechanism (30), and a shock absorber (40). The inner tube (20) is vertically movable disposed in the outer tube (10) and includes a head (21) located outside the outer tube (10) and a bottom (11) situated inside the outer tube (10). The height adjustment mechanism (30) is located inside the inner tube (20) and is configured to drive the inner tube (20) to move relative to the outer tube (10). The height adjustment mechanism (30) includes a stopper (34) positioned above a stop flange (23) on an inner wall of the inner tube (20) and can be abutted against the stop flange (23). The shock absorber (40) has two ends respectively abutted against the head (21) of the inner tube (20) and the stopper (34). The above-described design of the seatpost can prevent the saddle from being raised to an unexpected height for the rider.