Abstract: Seven 5-bromo-2-hydroxy benzoyl substituted aromatic aldehyde hydrazones were synthesized with methyl salicylate as raw materials via bromination,hydrazination and condensation reactions,respectively.Three novel compounds were reported.The structures of all the synthesized compounds were confirmed by ¹H NMR,IR,mass spectra and elemental analysis.The result of preliminary bioassay shows that the title compounds have obvious selective antibacterial activities to different classificatory bacterium at 0.05%(mass concentration),and have 100% inhibitory rate on Monilia albican and Bacillus subtilis.They will be a kind of potential antibacterial compounds against fungus and Gram-positive bacteria.5-Bromo-2-hydroxyphenyl-3',5'-dibromo-o-hydroxyphenyl substituted aromatic aldehyde hydrazone has the same antibacterial activity as triclosan.The analysis of structure activity shows that the antibacterial activities are related to the kind of Ar-ring and its substituent groups.The antibacterial activities are reduced by electron-donating groups,such as o-,p-OH,—OCH₃ of Ar-ring,however,they are enhanced by the m-substituted halogen groups of Ar-ring.