Abstract: During long-term service, submarine cables are subject to various factors such as ocean currents, geological evolution, corrosion, and anchor strikes, resulting in a wide range of complex failure modes. Accurately assessing the risk of submarine cable failure is beneficial for understanding the operational status of submarine cables, preventing and handling submarine cable failures in advance, reducing accident rates, and improving service safety. In response to the problems of multiple failure modes and triggering factors of submarine cables, as well as the difficulty of failure risk assessment, this paper summarizes the main failure modes of submarine cables and analyzes their probability and weight combined hierarchical analysis and fuzzy comprehensive evaluation methods. A fuzzy fault tree based submarine cable failure risk assessment method is proposed. Through engineering case analysis, the probability of submarine cable failure is determined to be 7.45 × 10⁻², and the hazard level is relatively low, which verifies the feasibility of the proposed method. Beneficial for taking protective measures in advance to reduce the probability of accidents and ensure the safe operation of submarine cables.