Sinusoidal negative Poisson’s ratio (NPR) honeycomb beam has unique mechanical properties useful for aerospace, architecture, and biomedicine. In this research, the sinusoidal NPR honeycomb beams made of polylactic acid were compared with the traditional ones of equal quality. The failure mode and energy absorption of the honeycomb beams with different NPR were studied by using the three-point bending test method. The energy absorption performance of sinusoidal NPR honeycomb beams was significantly dependent on the ratio of sinusoidal amplitude to period, which is better than that of traditional square-hole honeycomb beams. With the increase of NPR, its energy absorption performance gradually decreased. By optimizing the ratio of amplitude to period, the beam’s energy absorption performance was optimized while maintaining high stiffness and bearing capacity.