Aquatic products are an essential source of nutrition for humans, and their safety has attracted much attention due to the contaminations with pathogenic bacteria. Pathogenic bacteria such as Vibrio parahaemolyticus, Salmonella spp., Listeria monocytogenes, Escherichia coli, Staphylococcus aureus, and Shigella spp. could easily invade aquatic products through water contamination or cross-contamination during processing, causing foodborne diseases and economic losses. This article reviews the contamination routes and hazards of the major pathogenic bacteria in aquatic products, systematically summarizes the properties and application status of both conventional detection techniques (including selective medium method and plate counting method) and novel detection techniques, such as loop-mediated isothermal amplification and recombinase polymerase amplification.