A rapid multiplex-PCR method was established in order to detect four common foodborne pathogenic bacteria including Salmonella spp., Staphylococcus aureus,Vibrio parahaemolyticus and Shigella spp.in aquatic products.Four pairs of oligonucleotide primers were designed for multiplex-PCR amplification according to gene coding invasion protein A of Salmonella spp.,gene coding heat stable nuclease of Staphylococcus aureus,gene toxin regulatory protein of V.parahaemolyticus and invasion plasmid antigen H gene of Shigella spp.The amplified fragment sizes of these four bacteria were 549 bp,426 bp,348 bp,243 bp,respectively.Then four main factors of multiplex-PCR system were optimized,also the specificity and sensitivity of this method was detected.The final 50 μL reaction mixture contained 1.2 μL nuc primers,1.2 μL ipaH primers,1.6 μL toxR primers,1.6 μL invA primers,0.6 μL Taq enzyme,3.5 μL Mg²⁺,4 μL dNTP and 1 μL DNA template for each bacterium.The sensitivity was as low as 10 CFU/mL for Salmonella spp.,Vibiro parahaemolyticus and 10² CFU/mL for Shigella spp.,S.aureus.A general enrichment broth was optimized to allow simultaneous growth of these four bacteria in samples.The multiplexPCR method was used to analyze 35 aquatic product samples compared with national standard methods,the coincidence rate of two methods was greater than 95% and there was no significant difference between these two methods(P＞0.05).Therefore,it was suggested that the method developed in this study had high sensitivity and specificity,and could be applied for the rapid detection and molecular epidemiology survey of foodborne pathogenic bacteria in aquatic products.