Abstract: The hexagonal boron nitride (hBN) nanoparticles were surface modified by silane coupling agent KH550. The different mass fractions (0.05%, 0.10%, 0.15%, 0.20%) of hBN modified polyurethane acrylate (hBN/PUA) composites were prepared by stereolithography technology. The effect of hBN content on the mechanical properties and dry friction and wear properties of the composites was studied. The results show that with the increase of hBN content, the tensile and bending strengths of the composites first increased and then decreased, while the stable friction coefficient and wear mass loss first decreased and then increased. When the mass fraction of hBN was 0.10%, the tensile strength and bending strength of the composites were the highest, which increased by 35.87% and 36.92% compared with those of pure PUA, respectively; the stable friction coefficient and wear mass loss were the smallest, which decreased by 31.03% and 45.83% compared with those of pure PUA, respectively. At this time, the mechanical and wear resistance of the composites were the best. When the mass fraction of hBN was not larger than 0.10%, hBN particles were evenly distributed in the PUA matrix, hindering crack propagation, resulting in improvement of strength and wear resistance. When the mass fraction of hBN was larger than 0.10%, the hBN particles agglomerated, resulting in stress concentration, and the strength and wear resistance decreased.