Thin-walled structures are used extensively in the passive safety of vehicles to absorb energy. The thin-walled tube is already a traditional structure with excellent energy absorption. Negative Poisson's ratio (NPR) structures produce an inward concentration to increase the stiffness of the structure during axial compression. The concept of fluctuation of crushing force (FoCF) is introduced herein to evaluate this new energy-absorbing box as an energy-absorbing device based on the traditional energy absorption evaluation index. Based on experimental validation, a finite-element model is developed that can accurately predict the crashworthiness of the double-V NPR-filled square tube (DVFST). The following parameters, such as out-of-plane thickness, meta-cell half-width beam thickness, and beam angle tube thickness, are conducted to assess the crashworthiness of the DVFST structure. The first thing that should be considered in the design of the DVFST structure is the half-width of the cell, followed by the angle of the long beam, and then the relative wall thickness of the long and short beams. The DVFST structure has the potential to become an excellent energy-absorbing device by adjusting its parameters.