The large cylinder breakwater is subjected to horizontal loadings,vertical loadings or the combination of those loadings generally.The type of the structure and the penetration depth can influence the bearing capability of large cylinders when subjected to the combination of horizontal and vertical loadings.The swipe loading model with displacement loading control method is adopted to calculate the bearing capability of large cylinders in different radios of penetration depth to its diameter.According to the results of numerical stimulation,the bearing capability in horizontal direction increases dramatically in a linear relationship.However,the bearing capability in vertical direction,though in the beginning,increases,then tends to become stable in the following situations.Furthermore,the plastic penetration area appears in the soil on both sides of the large cylinders when the penetration depth to the soil is in a lower level,while it changes to appear on one side of the large cylinders along with the increasing of the radio of penetration depth to the diameter.In the end,the failure envelope of large cylinders subjected to the combination of horizontal and vertical loadings turns out to be convex ellipse,the radius of which increases when the penetration depth getting larger.Besides,the normalized failure envelope can be expressed in the exponential form of V/Vult and H/Hult。