Abstract: Honeycombs with negative Poisson's ratio (NPR) have garnered significant attention due to their exceptional energy absorption and anti-indentation properties. However, existing NPR structures are typically characterized by high equivalent elastic moduli, limiting their applicability in scenarios demanding high flexibility and large deformations. This paper proposes a novel arrowhead-shaped NPR honeycomb structure. Utilizing the energy method, the theoretical expressions for its equivalent tensile modulus, Poisson's ratio, and equivalent density were derived. Furthermore, the influence of various geometric parameters on its equivalent mechanical properties is systematically investigated. The established theoretical model undergoes rigorous validation through systematic finite element analysis and quasi-static tensile testing, with results demonstrating highly consistent agreement. Results show that the equivalent elastic modulus of this novel structure is only 5.34% of that of the classic re-entrant hexagonal honeycomb structures. This unique combination of low modulus and negative Poisson's ratio properties endows the proposed honeycomb structure with outstanding application potential in fields such as flexible structure, deployable structures, and biomedical scaffolds.