To identify effective biocontrol bacteria antagonistic to tobacco brown spot disease, we isolated and screened bacterial strains from tobacco rhizospheric soil using dilution plating and plate confrontation methods, with Alternaria alternata as the indicator organism. The antimicrobial activity of fermentation broth was determined using the mycelial growth rate method. Strain identification involved morphological observations and 16S rRNA sequencing. The strains were evaluated for broad-spectrum