Induced mutation of Lactobacillus plantarum fmb10 divided from pineapple was performed by Co⁶⁰γ, low-energy N⁺ beam irradiation, DES, EMS and composite mutagenesis, respectively, to enhance the antibacterial activity. The results showed that Lactobacillus plantarum fmb10 was sensitive to low-energy N+ beam and EMS irradiation, and a high-activity strain fmb10-Z with stable inheritance and forward mutation was obtained after the treatment of EMS-low-energy N⁺ beam composite mutagenesis. The bacteriostatic diameter against E.coli was increased by 23%, and the antibacterial activity of the mutant fmb10-Z was increased 1.5 times compared with original strain.