The work aims to develop a shock absorber for a transport cask and investigate the effects of the size of the shock absorber and the dispersion of the filling material on the design of the shock absorber. The effect of shock absorber size on the damping effect of the transport cask was analyzed and calculated. The dispersion of wood compression strength was obtained by compressive strength test of wood, and the 9 m over center of gravity angle drop analysis of the transport container was carried out through the finite element method. And the 9 m over center of gravity angle drop test was carried out for verification.Generally speaking, the larger the size of the shock absorber, the more energy it absorbed; but if its size exceeded a certain point, the damping effect decreased instead. The filling wood of low compressive strength absorbed less energy than that of high compressive strength. But when the compressive strength of the filling wood was large, the rigid shock absorber would lead to the peak acceleration of the rigid cask body. The shock absorber is well designed and meets the specification requirements. The mechanical property dispersion of the filling wood will have an impact on the design. Therefore, with the use of wood as a cushioning and shock absorption filling material, the impact of wood compressive strength dispersion of the cushioning effect should be considered.