Abstract: In order to improve the sound absorption characteristics of the traditional honeycomb sandwich panel structure, a negative Poisson's ratio concave hexagonal honeycomb sandwich panel structure was proposed, the upper panel of the structure was a micro-perforated plate, and the sandwich layer was a negative Poisson's ratio concave hexagonal honeycomb, which was composed of 19 units cavity resonators with internal extension tubes. The sound absorption coefficient of the concave hexagonal honeycomb sandwich plate structure in the frequency range of 500-950 Hz was calculated by COMSOL simulation software, and the validity of the simulation results was verified by the B&K standing wave tube measurement system. Under the premise of keeping the structure of negative Poisson's ratio concave hexagonal honeycomb cell unchanged, the influence of cell parameters on the sound absorption coefficient of honeycomb sandwich plate structure was studied. The results show that when the cell inclination angle increases, the porosity of the inner extension tube decreases, and the wall thickness of the cavity decreases, the sound absorption performance of the structure is enhanced. In addition, the increase of cavity depth and the increase of inner extension tube length will lead to the resonance frequency moving to lower frequencies, and the change of cavity depth is more obvious. In the frequency range of 500-950 Hz, the average sound absorption coefficient of the structure is increased by 5.64% compared with the traditional honeycomb sandwich panel structure, indicating that the negative Poisson's ratio has better sound absorption performance in the low frequency range than the traditional honeycomb sandwich panel structure.