Taking the 200，000 ton automated container terminal as an example，this paper uses the large-scale general finite element software to model the caisson and the large cylinder structure as a whole，and to model the superstructure separately，meanwhile，it studies the characteristics of the front toe stress and the internal force of the breast wall under the combined load. The research results reveal that the base bed of the front toe of the large cylinder dock has large stress and uneven distribution，while the base bed of the square caisson dock has little stress and relatively uniform distribution. The chest wall of the large cylinder dock has a large span and a large bending moment of the cantilever，while the chest wall of the square caisson dock has a small bending moment and the overall distribution is relatively uniform. For large gravity docks，the square caisson structure is more rationally stressed than the large cylinder structure.