Additive manufacturing has received attention for the fabrication of medical implants that have customized and complicated structures. Biodegradable Zn metals are revolutionary materials for orthopedic implants. In this study, pure Zn porous scaffolds with diamond structures were fabricated using customized laser powder bed fusion (L-PBF) technology. First, the mechanical properties, corrosion behavior, and biocompatibility of the pure Zn porous scaffolds were characterized in vitro. The scaffolds were then implanted into the rabbit femur critical-size bone defect model for 24 weeks. The results showed that the pure Zn porous scaffolds had compressive strength and rigidity comparable to those of cancellous bone, as well as relatively suitable degradation rates for bone regeneration. A benign host response was observed using hematoxylin and eosin (HE) staining of the heart, liver, spleen, lungs, and kidneys. Moreover, the pure Zn porous scaffold showed good biocompatibility and osteogenic promotion ability in vivo. This study showed that pure Zn porous scaffolds with customized structures fabricated using L-PBF represent a promising biodegradable solution for treating large bone defects.