Artificial bone is the alternative candidate for the bone defect treatment under the circumstance that there exits enormous challenge to remedy the bone defect caused by attributes like trauma and tumors. However, the impact of pore size discrepancy for regulating new bone generation is still ambiguous. Using direct 3D printing technology, customized 3D polycaprolactone/-tricalcium phosphate (PCL/-TCP) artificial bones with different structural pore sizes (1.8, 2.0, 2.3, 2.5, and 2.8 mm) were successfully prepared, abbreviated as the 3D PCL/-TCP. 3D PCL/-TCP exhibited a 3D porous structure morphology similar to natural bone and possessed outstanding mechanical properties. Computational fluid dynamics analysis indicated that as the structural pore size increased from 1.8 to 2.8 mm, both velocity difference (from 4.64 × 10to 7.23 × 10m s) and depressurization (from 7.17 × 10to 2.25 × 10Pa) decreased as the medium passed through.biomimetic mineralization experiments confirmed that 3D PCL/-TCP artificial bones could induce calcium-phosphate complex generation within 4 weeks. Moreover, CCK-8 and Calcein AM live cell staining experiments demonstrated that 3D PCL/-TCP artificial bones with different structural pore sizes exhibited advantageous cell compatibility, promoting MC3T3-E1 cell proliferation and adhesion.experiments in rats further indicated that 3D PCL/-TCP artificial bones with different structural pore sizes promoted new bone formation, with the 2.5 mm group showing the most significant effect. In conclusion, 3D PCL/-TCP artificial bone with different structural pore sizes could promote new bone formation and 2.5 mm group was the recommended for the bone defect repair.