Abstract: The poly (lactic acid) (PLA)/nano-gallium oxide (NGO) composite fiber membranes were prepared by an electrospinning technology and the morphology, crystalline properties and mechanical properties were inveistigated by scanning electron microscopy, differential scanning calorimetry and universal testing machine, respectively. Moreover, the antibacterial performance of the membranes was evaluated by an oscillation flask method. Morphological observation indicated that the diameter of composite fibers decreased with an increase of NGO content and their diameter distribution also became broad. Thermal analysis results indicated that the melt temperature and crystallinity degree of the membranes demonstrated an increasing trend at first and then began to decrease with an increase of NGO content. Mechanical evaluation indicated that the fracture strength and elastic modulus of the membranes increased at first and then decreased with an increase of NGO content, but their elongation at break showed a decrease at first and then an increase. The composite fiber membranes also presented a good antibacterial property against Staphylococcus aureus, and their antibacterial effect was enhanced gradually with increasing the NGO content.