Abstract: In the aerospace and automotive manufacturing industries, the combination of selective laser sintering and adhesive joining have shown promising approach for realizing lightweight and efficient structural systems. However, there are still no systematic studies on the structure-performance relationship of the adhesive bonded SLS composite parts. In this paper, the effects of building directions and fiber orientation on the bonding performance of the carbon-fiber-reinforced polyamide 12 coupons manufactured by selective laser sintering were studied. For double cantilever beam joining, the mode I interlaminar fracture toughness (G_IC) of the side surface is nearly 4 times higher than that of the top surfaces, and 2.5 times higher than that of the bottom surfaces. We identified the improvement in fracture properties as a combination of higher surface roughness and fiber orientation. As the fiber is perpendicular to the bonding surface, the fiber tear failure can be suppressed to the greatest extent, thereby obtaining the highest fracture toughness (G_IC=2 600 J/m²). The research results provide data support for the development of lightweight equipment.