Abstract: To address the issues of delamination damage, plastic fracture, and insufficient energy absorption in composite porous structures under compression, a partial stiffness enhancement design method is proposed. Utilizing 3D printing technology, locally stiffness-enhanced models with regular hexagonal and re-entrant hexagonal honeycomb unit cells were fabricated. Combining polylactic acid (PLA) and carbon fiber (CF) materials, the effects of geometric parameters (reinforcement rib height H, thickness D) on deformation modes, load-bearing capacity, and energy absorption were investigated. Experiments demonstrate that partial stiffness enhancement significantly improves fracture resistance and energy absorption. For PLA material, the regular hexagonal unit cell (H = 2.5 mm, D = 1.5 mm) exhibits a 9.6% increase in specific energy absorption (SEA), while the concave hexagonal unit cell (H = 3 mm, D = 2 mm) achieves a 192.2% enhancement in peak load-bearing capacity. For CF material, the regular hexagonal unit cell (H = 3 mm, D = 2 mm) shows a 35.0% improvement in specific energy absorption, with the concave hexagonal configuration demonstrating SEA stability. Larger geometric parameters H and D consistently improve both load-bearing capacity and energy absorption performance. Analysis of porous structures reveals that concave hexagonal cells increase SEA by 55.4% (PLA) and 88.8% (CF) compared to regular hexagons, while also entering the densification stage earlier. The CF-based porous structures resist delamination damage, primarily undergoing plastic deformation with extended plateau stages, which results in 29.4% higher specific energy absorption than PLA-based structures.