Abstract: To address the limitations of conventional crash boxes, particularly their restricted energy absorption efficiency and excessive primal impact forces, a novel crash box with negative Poisson's ratio was designed through topology optimization methodology in this paper. A multi-dimensional verification framework integrating convergence analysis, finite element modeling, and experimental calibration was established to validate the structural configuration. The dynamic response characteristics under impact velocities of 3 m/s, 20 m/s, and 100 m/s were systematically investigated using explicit dynamics simulations. Results demonstrate that the proposed crash box shows a lower primal impact force and a higher mean impact force compared with conventional square crash boxes across all tested velocity regimes. Total energy absorption capacities show 293.6%, 302.9%, and 178.2% enhancements respectively, accompanied by specific energy absorption improvements of 31.6%, 34.5%, and 2.7% under progressive impact conditions.