PLA fibers were electrospun from a PLA (polylactic acid) solution in mixed solvent of methylene chloride/ethyl alcohol (80/20). In order to prepare PLA fibers from electrospinning with Streptomycin (0.1 wt% - 0.5 wt% to the amounts of PLA) as a antibiotics material in methylene chloride/ethyl alcohol (80/20). PLA solutions were electrospun at 15kV positive voltage. 10 cm tip-to-collector distances(TCD). 100 ul/min solution flow rate . The PLA nanofibers were characterized by SEM (Scanning electron microscopy). Antimicrobial activities of nanofibers was evaluted by disc diffusion test optical density test and colony counting test against E. Coli and S. Aureus.