The stability of the quay wall incorporating large diameter cylinders is of great concern at the Yangshan Port, China, owing to severe marine environment. In this study, finite element analysis is carried out to evaluate the stability of a trial quay wall during construction. The single cylinder is examined in terms of turnover failure subjected to a five year design wave action. The case when the cylinder is empty is the critical situation during construction. Filling the cylinder right after the installation is an effective way to increase the stability. After the quay wall has been formed by joining the single cylinders, the safety against overturning is reevaluated. The factor of safety of the quay wall is assessed to be 1.5 under a fifty year design wave action.