Objective: PLA has a broad application prospect in biomedicine because of its degradability and good biosafety. However, direct application of PLA in the clinic may cause local inflammatory reaction or infection due to its acidic degradation products and lack of antibacterial properties, resulting in poor healing of local tissues and even implantation failure. Therefore, the preparation of functional composites with antibacterial properties is a feasible choice for improving the properties of PLA. Methods: In the present study, Mg/PLA composite membranes were prepared by loading different proportions of Mg particles into PLA matrix for guided bone regeneration. MC3T3-E1 cell line, L929 cell line, E.coli and S.aureus were used to determine their biocompatibility and antibacterial properties. Results: Results show that 20%wt Mg/PLA and 40%wt Mg/PLA composite membranes had obvious antibacterial functions, and the antibacterial rate increased with the increase of Mg content. However, it can not be ignored that the high Mg content weakens the enhancement effect of Mg particles on the mechanical properties of PLA. Conclusion: Mg/PLA composite material has a good improvement on the mechanical properties and antibacterial effect of polymer, expecting to be used as a barrier membrane material for GBR.