Abstract: The nano Ag-polyvinyl butyral (PVB) composite nanofibers were prepared by electrospinning method, which aimed to fabricate antibacterial and efficient air filtration material. The morphology of nano Ag was characterized by TEM. The microstructure, chemical structure and crystal structure of the as-prepared nano Ag-PVB composite nanofibers were confirmed by SEM, FTIR and XRD. Moreover, the filtration efficiency, air permeability and antibacterial performance of the composite nanofibers were further studied. The results indicate that the suitable component for preparing composite nanofibers is 10wt% PVB and 0.25wt% nano Ag in ethanol solvent. Under the operating condition, the nano Ag-PVB composite nanofibers exhibit uniform structure with fiber diameter of 542.14 nm. The air filtration performance test reveals that the optimized electrospinning time is 10 min. Moreover, the nano Ag-PVB composite nanofibers display excellent PM2.5 filtration efficiency of 99.99%, low pressure drop of 16 Pa and appropriate air permeability of 155.0 mm/s. Further antibacterial test demonstrates that the nano Ag-PVB composite nanofibers exhibit good antibacterial performance for E.coli, and the antibacterial rate is 95.52%.