Trachinotus ovatus) causing rot body disease in the deep-sea cage aquaculture area in Houshui Bay, 2016. Building a more rapid, accurate, and convenient technical detection analysis rather than the conventional methods, for example, physiological and biochemical identification, 16S rRNA gene sequence analysis, and immunodiagnostic technique, which are labor-intensive and time-consuming, is of great importance to disease prevention and control. According to the principle of the LAMP method, real-time loop-mediated isothermal amplification (RT-LAMP) techniques were developed for detection of fish pathogenic V. harveyi QT520 after adding fluorescent dye SYTO-9 to the reaction system. The results showed that this method could effectively distinguish the , and the detection limit of this method for with both of pure cultures and DNA concentrations were found to be 10³ CFU/reaction and 100 fg/uL, being equivalent to real-time PCR (RT-PCR), which was 1000 and 10 times that of general PCR, respectively. Furthermore, the detection process through this method only took 40 min and the results could be displayed on the LCD panel. Thus, it has high specificity, high sensitivity, and the interpretation of results is simple and objective. Furthermore, it has simple operation characteristics, being suitable for application and promotion in basic levels of fishery technology promotion departments and fishery professional cooperatives.