Titanium alloys are widely used in dental implants due to their superior biocompatibility and mechanical strength. However, these alloys are prone to corrosion and wear in the oral environment, thereby shortening their clinical lifespan. This study investigates the enhancement of titanium alloy surface properties using magnetic abrasive finishing (MAF) and examines the influence of magnetic needle diameters (0.2–1.5 mm) on surface modification. Titanium alloy samples were processed by MAF and systematically evaluated for surface morphology, grain size, surface hardness, residual stress, electrochemical corrosion behavior, and tribological performance. Results demonstrated that MAF improves surface morphology, significantly refines grain size, and enhances surface hardness and compressive residual stress, thereby optimizing surface properties. The 1.0 mm magnetic needle group demonstrated the best performance, achieving a Vickers hardness of 376.71 ± 12.48 HV and a compressive residual stress of −579.1 ± 8.49 MPa. In addition, this group showed a higher self-corrosion potential (−0.5661 V), a lower corrosion current density (0.0114 μA·cm⁻²), and the lowest wear rate ((4.49 ± 0.42) × 10⁻⁴ mm³/N·m) in artificial saliva, demonstrating superior corrosion and wear resistance. Overall, MAF technology markedly enhances the surface integrity of titanium alloys in artificial saliva through the synergistic effects of grain refinement and stress modulation. These findings provide valuable experimental evidence supporting future efforts to optimize the surface properties of titanium alloy dental implants.