The metallic NPR metamaterials designed in this study are based on re-entrant lattice structures. Re-entrant structures are known to be one main class of auxetic structures that display negative Possion’s ratio, which can be manufactured by 3D printing technology. This kind of metamaterial has good designability. We can change its overall mechanical properties by changing its geometric parameters. In order to achieve better impact performance, the structure can be designed into some gradient types. The mechanical properties of different gradient structures under the same impact conditions were compared to find the proper gradient structures. On the other hand, the impact performance can also be changed by the impact conditions. The initial impact velocity was changed to study the effect of impact conditions on the mechanical properties of the gradient structure. Based on the studies, we applied the lattice structure to the automobile energy absorbing box. We made some simulation by the finite element software LS-DYNA of vehicle head-on collision. We compared the crashworthiness of the cars which have different energy absorbing boxes. The accelerations of some key points in the crew compartment were measured. Also, we compared the energy absorption efficiency of the boxes. We came to the conclusion that the gradient lattice structure can efficiently improve the crashworthiness of the car and also achieve some weight reduction of the vehicle structure. Because the lattice structure has good impact performance, some other vehicle structures which need to have a good impact behavior can also be replaced by it .