To ensure the operation safety of ocean intervention, a digital twin of intervention system was constructed. A five-dimensional digital twin system for marine coiled tubing intervention was designed, which included the physical assets, virtual assets, data interaction between virtual and real world, artificial intelligence data analysis and operation decision support modules. A three-dimensional model was constructed by SolidWorks software, and then was imported into Unity 3D for scenes simulation. A virtual assets model of ocean intervention system was built, and the visualization interactivity was enhanced using virtual reality technology. Equipment was monitored based on OPC UA protocol through real-time and historical data collected by Programming Logic Controller (PLC). Data analysis was made with MATLAB software, and the intervention response model was constructed, which could design operation strategies for achieving effective fault diagnosis and prediction. The discussion of a case showed the feasibility of the proposed method.