Luminescent bacteria biotoxicity and inhibition on dehydrogenase activity by phenol and its derivatives were studied in this paper.The results showed that: the order of luminescent bacteria biotoxicity of the five phenolic compounds was 2,4-dichlorophenol>p-nitro-phenol>o-methyl-phenol>phenol> p-amino-phenol,and the value of EC 50 was 4.95,23.90,42.43,83.65 and 178.75 mg/L respectively.The order of inhibition on dehydrogenase activity by phenol and its derivatives was different from that of luminescent bact...