Based on the modular structure, effects of different module filling methods and dovetail geometry parameters of module connection on the failure modes and energy absorption characteristics of the overall structure are investigated under uniaxial compressive loading. The results show that when the model filling modes are hexagonal and auxetic cell elements filling, the upper-left, lower-middle, and upper-right parts start deforming first, and the connecting parts are all subjected to shear failures. When the overall filling mode is half-filling, the growth rate of the force-displacement curve is more stable, and the efficiency of the compression force is larger. Energy absorption is better when the overall filling pattern of the model is hexagonal unit element filling. The efficiency of the compression force can be improved when the angle α of the connection part is 60° and the width of the connection part is 12mm. The energy absorption effect can also be improved when the angle α of the connecting part is 65°.