The invention discloses a self-adjustable combined impact energy absorber comprising an upper pad, a lower pad and a plurality of middle single energy-absorbing cylinders. The self-adjustable combined impact energy absorber has four equal single energy-absorbing structures. Each single energy-absorbing structure is provided with circular grooves along the length L of the corresponding thin-walled cylinder, the circular grooves have different depths h0 to h0-nt, and spacing of each two circular grooves is W. The grooved part of the wall of each cylinder is thin; the circular grooves are different in depth along the length L of the cylinder. The self-adjustable combined impact energy absorber allows recovery of an impact angle during asymmetric impact, stability of an energy-absorbing mechanism can be effectively guaranteed, absorbing capacity magnitude drop caused by asymmetric deformation is controlled, and good absorbing effect is achieved in both cases of direct impact and oblique impact.