In order to clarify the effect of cell size on the axial load capacity and compression properties of hexagonal thin-walled honeycomb structures, hexagonal 18Ni300 thin-walled honeycomb samples of 10 mm in diameter, 15 mm in height and 0.1 mm in thickness with different cell size of 1.75 mm, 2.25 mm, 2.75 mm and 5 mm filled were fabricated by selective laser melting. Static axial compression tests of the samples were performed, and load capacity and specific energy absorption performance of the samples were analyzed. Results show that the samples with cell size above 2.25 mm are compressed by stacking during compression, and the load capacity per unit volume and specific energy absorption increase as the cell size decrease. However, for the sample with cell size of 1.75 mm, it is damaged by outward tearing mode during axial compression with significant decrease of load capacity per unit volume and specific energy absorption.