Abstract: TC4 titanium alloy samples with artificial implant defects were prepared by Selective Laser Melting (SLM) for one of the additive manufacturing technologies. The effects of the size and location of artificial implant defects on the tensile properties of the fabricated alloy at room temperature were studied, respectively. The results show that the actual size of the defects is slightly smaller than the designed size due to the alloy powder contained in the SLM fabrication process not being discharged but sintered on the hole defect surface after heat treatment. When the embedded defect diameter is less than 0.7 mm, the tensile strength of the alloy remains unchanged, and the samples all break from the non-embedded defect area. When the diameter of the embedded defect exceeds 0.7 mm, the tensile strength significantly decreases with the increase in defect size, and the samples all break from the embedded defect area. Alloy elongation is significantly affected by defects. With the increase in defect size, the overall elongation shows a trend of gradual decrease. When the defect size exceeds 0.7 mm, the elongation decreases sharply. When the defect size exceeds 0.9 mm, the elongation fluctuates in the range of 2%—4%. When the defect size is more than 0.7 mm, defect size is the dominant factor affecting the strength and elongation of addictive manufacturing alloy.