In order to screen out highly effective antifungal bacterium,which can be well colonized in the rhizosphere,root and leaf of tomato and has good control effect on tomato gray mold,the methods of plate screening,field screening,rifampicin resistance marker,morphological identification,physiological and biochemical identification,16S rRNA,gyrA and gyrB identification were used to screen and study the colonization characteristics and taxonomic status of highly efficient antifungal bacteria against Botrytis cinerea.The results showed that among 58 strains,strain ZSY-1 had more significantly antifungal activity against B.cinerea than other strains and had more than 75% antifungal activity against B.cinerea in indoor and field trials.Although the colonization characteristics of strain FG-6 in tomato rhizosphere (1.76×10⁶cfu/g),root system(1.54×10⁶cfu/g)and leaf(0.87×10⁶cfu/g) were significantly better than strain ZSY-1(rhizosphere:1.67×10⁶cfu/g;root system:1.46×10⁶cfu/g;leaf:0.64×10⁶cfu/g),but its field control effect was only about 30%,which was significantly lower than strain ZSY-1. Strain ZSY-1 was identified as Bacillus velezensis based on morphology,physiological and biochemical characteristics,16S rRNA,gyrA,and gyrB genes.The above results determined that strain ZSY-1 might be an excellent candidate strain against B.cinerea for the development of biological agents.