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 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, main failure modes of submarine cables, including their probability and weight, were summarized and analyzed. Combined hierarchical analysis and fuzzy comprehensive evaluation (FCE), risk assessment of submarine cable failure based on fuzzy fault tree was proposed. Through engineering case analysis, the probability of submarine cable failure was determined to be 7.45×10⁻², and risk level was relatively low, which verified the feasibility of the proposed method. The method was beneficial for taking protective measures in advance to reduce the probability of accidents and ensure safe operation of submarine cables.