Abstract: Proposing an I-shaped bionic densified reinforced honeycomb cores design based on the microstructure of spruce trees. Through a three-point bending test, the load-displacement curves and failure modes of ordinary carbon fiber/aluminum honeycomb sandwich panels and I-shaped bionic densified reinforced carbon fiber/aluminum honeycomb sandwich panels were compared and analyzed. The test results show that the I-shaped bionic densified core design significantly improves the bending stiffness, peak load, and energy absorption performance of the test specimens. Compared with the non-densified specimens, the average values of peak load, specific peak load, energy absorption, specific energy absorption, and bending stiffness of the dense specimens increased by 61.8%,49.5%, 36.7%, 23.6%, and 27.1%, respectively. Observation of the failure mode of the test specimen revealed that the densified reinforced honeycomb core sandwich panel effectively resisted buckling and shear failure of the honeycomb. The presence of the densified band altered the load transfer path and deformation pattern of the traditional aluminum honeycomb core, significantly enhancing the specimen's load-bearing capacity and energy absorption. Finite element models were established for both plain carbon fiber/aluminum honeycomb sandwich panels and I-shaped bionic densified sandwich panels. The simulation analysis results showed an error of less than 6% compared to the experimental results, validating the accuracy and reliability of the models.