Abstract: The surrounding marine ecological environment and the economic and social development will be seriously harmed if any oil spill of large oil tankers occurs at sea. Therefore, it is important to enhance the accuracy of risk assessment for oil spill of large oil tankers. Take the waters of the Cape Good Hope in Africa as an example. A risk evaluation index system for oil spill of large oil tankers in the waters of Cape of Good Hope was established with the fuzzy comprehensive evaluation method from the four aspects, i.e. human factors, ship factors, environment factors and management factors, and the risk level of oil spill was evaluated according to the collected data of the large oil tankers through the waters. It is concluded that the oil tankers are at moderate risk of oil spill there. Definitely, the crew's sense of responsibility and wave height are the main factors affecting the oil spill risk of large oil tankers. In general, the new evaluation method provides a theoretical basis for the avoidance of risk of large oil tankers, which is benefit to guarantee the safety of life and property of the crew and the balance of the marine ecosystem.