The advanced metamaterials concept has been widely explored and utilized in many industries, ranging from automotive applications to medicine, and has great potential in the aerospace field. Novel nature-inspired 3D printed double-graded aluminum foam-filled negative Poisson's ratio metamaterials (DGAT) were designed, fabricated, and investigated. Their mechanical properties were examined by the finite element method and experiments. The geometrical parameters and combination types show different effects on the mechanical properties of DGAT metastructures. Under axial compressive loading, the DGAT structure has a lower peak force and higher specific energy absorption. Then, parametric analysis shows that several design parameters (e.g. m, T, θ, tmin, tmax) have a very strong effects on the mechanical performance. Finally, multi-objective optimization is performed to maximize specific energy absorption while reducing maximum impact force. Optimization results show that the novel graded metamaterials have stronger energy absorption capacity than the ordinary counterparts. Especially, the specific energy absorption can be increased to 80% with 15% peak loading force rising. Due to their unique structural design and excellent mechanical properties, the DGAT metastructures have great potential applications in the fields of transportation protection, military protection engineering, manned spacecraft cushioning and energy-absorbing boxes.