The operating status of submarine cables directly affects the safety and reliability of offshore engineering. It is of significance to timely and effectively obtain the health status of submarine cables. Due to the complex structure and operating environment of submarine cables, it is difficult to accurately obtain the health status of submarine cables. Therefore, a comprehensive health status assessment method of submarine cables with online monitoring data is proposed. Firstly, following technical guidelines of cable status evaluation, an index system suitable for submarine cable comprehensive health status evaluation is constructed by integrating static data, such as patrol inspection and testing data and dynamic data from online monitoring. Secondly, a set of reasonable and evidence-based evaluation criteria is formed based on the characteristics of online monitoring status of submarine cable and evaluation standards from cable guidelines. Then, on the basis of the above, a multi-state fusion based status evaluation model is established, which can evaluate the overall submarine cable as well as its components hierarchically to obtain its health status. Further leveraging fuzzy theory, a comprehensive health status of the submarine cable can be obtained. Finally, the feasibility and effectiveness of the proposed method is verified by applying on submarine cables in a practical offshore oil and gas project.