The aim of this study was to investigate Lactobacillus plantarum IMAU10014’s growth promotion effects on tomato, biocontrol efficacy on Botrytis cinerea caused disease and its induction effects on several defense-related enzymes. Seed-soaking with IMAU10014 was used for determining its growth promotion effects on tomato, and leaf spraying and root soaking inoculation were employed to determine its biocontrol effectiveness. Seed-soaking with IMAU10014 at concentrations of 107 CFU/mL for 6 to 8 h significantly increased seed germination rates and buds size. Seed germination rate was 100%. Treatment of tomato seedlings with L. plantarum IMAU10014 reduced B. cinerea disease index from 47.22 to 32.41 and 26.39 (Biocontrol effect 31.36% and 44.11%), respectively. Significant induction of plant defense-related enzymes, including phenylalanine ammonia-lyase (PAL), peroxidase (POD) and polyphenol oxidase (PPO) was observed in tomato plants treated with L. plantarum IMAU10014. L. plantarum IMAU10014 has good potential as a biological pesticide to control Botrytis blight.