To measure the operational risks of the mechanisms of vertical ship lift systems，this study focuses on the coupling among those mechanisms and the fuzziness of the operational risks and builds a fuzzy measurement model for those operational risks by integrating the decision-making trial and evaluation laboratory（DEMATEL）method with the fuzzy theory. It analyzes the coupling of the operational risks of a vertical ship lift with the risk factors from the perspective of the different operating conditions of the vertical ship lift. Then，it builds an index weighting model based on the DEMATEL method，develops a fuzzy measurement method for the operational risks of the mechanisms of the vertical ship lift system，and analyzes the Three Gorges’ vertical ship lift as an example. The results show that the operational risk level of the mechanisms of this vertical ship lift system is level IV，representing low risks. However，attention still needs to be paid to conditions that cause the unstable operation of the vertical ship lift. Such conditions include that water leaks in the gap between the ship chamber and the lock head，the ship chamber door cannot be opened and closed normally，the anti-collision device cannot be raised and lowered properly，the gap water cannot be filled and discharged as it should be，and the lock head door cannot be opened and closed correctly. Special attention should be given to the influence of the water surface fluctuation in the ship chamber on the operational safety of the vertical ship lift.