The aim of this study was to develop a magnetic bead enrichment-based method for the detection of Mandarin fish ranavirus in culture water. The results showed that the method was effective in enriching Mandarin fish ranavirus in culture water samples， and specific bands could be obtained by conventional PCR amplification. Quantitative analysis showed that the sensitivity of the magnetic bead enrichment method combined with real-time fluorescence quantitative PCR reached the detection limit of 0.01 copies/μL. Feasibility analysis demonstrated that the magnetic bead enrichment method had 90% concordance with qPCR results and was suitable for fully automated nucleic acid detection platforms. Compared with the traditional qPCR method， this method has better anti-interference ability and ease of operation while maintaining high detection consistency. The detection technology developed in this study is characterized by easy operation and high sensitivity， which provides reliable technical support for the monitoring of aquaculture water pathogens and early warning， and is of great practical significance for the prevention and control of aquaculture diseases.