Mechanical vibration and complex loading environment pose serious challenges to the reliability and service life of equipment structures, and new multifunctional material structures with both high load-bearing capacity and low-frequency broadband vibration damping characteristics are urgently needed. In this paper, we propose a vibration- and pressure-resistant integrated three-dimensional mechanical metamaterial beam, which realizes the synergistic regulation of static load-bearing and dynamic vibration-damping performance by integrating the pressure-resistant advantage of negative Poisson's ratio honeycomb core with the bandgap characteristic of local resonance metamaterial. Combined with finite element simulation and experimental verification, the influence of the vibrator arrangement on the bandgap characteristics is systematically investigated. The results show that the metamaterial beams form a broadband low-frequency damping bandgap of 436.3 Hz in the frequency band of 155.6–591.9 Hz when the ratio of the lattice constant to the size of the matrix element cell is 1:3, which is a 30.9% enhancement of the bandgap width compared with that of the beams with no vibrator matrix. Meanwhile, the pressure experiments verified the synergistic properties of high stiffness compressive load bearing and low stiffness frequency reduction, indicating that the structure is capable of both static compressive load bearing and dynamic low-frequency vibration damping performance. This study provides theoretical support and experimental basis for the multi-functional integrated design of mechanical metamaterials, which has an important application potential in the optimization of vibration and pressure resistant structures in marine engineering.