This study investigates the use of magnesium hydroxide (Mg(OH)₂) nanoparticles as a nanofiller in polylactic acid (PLA) to enhance the properties of 3D-printed bone scaffolds. The addition of 5 wt% Mg(OH)₂ significantly improved the mechanical properties of the PLA scaffolds, increasing tensile and compressive strengths by 20.50% and 63.97%, respectively. Mg(OH)₂ also accelerated the degradation of PLA through an acid-base neutralization reaction, with a 28-day mass loss rate of 15.40% for the PLA/20Mg(OH)₂ scaffold compared to 0.15% for PLA. The composite scaffolds exhibited sustained Mg²⁺ release for over 28 days, promoting apatite nucleation and growth, and enhancing biomineralization. Cell culture experiments showed that the addition of 5 wt% Mg(OH)₂ improved cell adhesion, proliferation, and osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs). The study concludes that Mg(OH)₂ can effectively address various issues related to PLA scaffolds, including degradation, mechanical properties, and biological interactions, making it a promising material for tissue engineering applications.This study investigates the use of magnesium hydroxide (Mg(OH)₂) nanoparticles as a nanofiller in polylactic acid (PLA) to enhance the properties of 3D-printed bone scaffolds. The addition of 5 wt% Mg(OH)₂ significantly improved the mechanical properties of the PLA scaffolds, increasing tensile and compressive strengths by 20.50% and 63.97%, respectively. Mg(OH)₂ also accelerated the degradation of PLA through an acid-base neutralization reaction, with a 28-day mass loss rate of 15.40% for the PLA/20Mg(OH)₂ scaffold compared to 0.15% for PLA. The composite scaffolds exhibited sustained Mg²⁺ release for over 28 days, promoting apatite nucleation and growth, and enhancing biomineralization. Cell culture experiments showed that the addition of 5 wt% Mg(OH)₂ improved cell adhesion, proliferation, and osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs). The study concludes that Mg(OH)₂ can effectively address various issues related to PLA scaffolds, including degradation, mechanical properties, and biological interactions, making it a promising material for tissue engineering applications.