Abstract: Two antagonistic bacteria 12 a and 14 b were obtained from the peach rhizosphere soil against Monilinia fructicola using serial dilution method and dual-culture inhibition on agar plate.12 a and 14 b were identified as Bacillus vallismortis and Bacillus altitudinis respectively by phenotypic, physiological, biochemical and 16 S rRNA gene sequence analysis. In vitro evaluation of antagonistic activity, the sterile fermentation filtrate and volatile metabolites of strain 12 a and 14 b both showed a strong inhibition on the mycelia growth of M. fructicola.Especially, the inhibitory effect of the volatile metabolites of strain 12 a was more significant ( p < 0.05) .For further study, in vivo tests indicated that fermentation broth and volatile metabolites of strain12 a and 14 b also delayed the onset of brown rot significantly ( p < 0.05) inhibited the development of lesion diameter of peach brown rot.