Abstract: To evaluate the N-acylated-L-homoserine lactones(AHLs)profiling of quorum sensing signal molecules of pathogen and spoilage bacteria from aquatic product,the technique of LC-MS/MS detecting simultaneously the AHLs was developed,compared with biosensor method.The results showed that Aeromonas hydrophila A2 and two strains of Pseudomonas aeruginosa secreted AHLs by biosensors Chromobacterium violacceum CV026 and Agrobacterium tumefaciens A136.The LC-MS/MS technique could be applied to qualitative and quantitative analysis of 11 kinds of AHLs.High levels of AHLs with 3-oxo-C₁₂-HSL and C₄-HSL being the most prominent were produced by P.aeruginosa and A.hydrophila,respectively.Low content of AHLs with C₄-HSL was secreted by S.putrefaciens XH4,whereas no AHLs were detected in Salmonella ATCC 14028-3,Escherichia.coli O157:H7 and three species of Vibro.The production of AHLs of P.aeruginosa ATCC 9027 increased with the growth of bacteria,and the highest level of AHLs was observed after 12 h culture.Thus,the LC-MS/MS methodology can provide comprehensive profiles and concentration of AHLs in single sample,with high accuracy and sensitivity.Furthermore,P.aeruginosa and A.hydrophila produced the higher level of AHLs of quorum sensing signal molecules among 11 strains of pathogen and spoilage bacteria from aquatic product,which will provide the good foundation to explore the mechanism and control of these bacteria.