Abstract: To investigate the failure modes of four-bucket foundation under V-H（rertical-horizontal load）,V-M（vertical-moment lood）,H-M（horizontal-moment load）and V-H-M（vertical-horizontal-moment load）,an overall model of four-bucket foundation with layered soil ground was established by means of ABAQUS based on a practical offshore wind project in Fujian,China. It shows that in V-H loading and H-M loading conditions,the vertical bearing capacity decreases as the horizontal load increases and the moment bearing capacity decreases proportionally with the increasing horizontal load. The motion pattern of four-bucket foundation changes from rotation to translation with the increase of vertical load under V-M combined loading condition. In V-H-M loading condition,the bearing capacity failure envelope will expand when the vertical load increases. The vertical load can obviously enhance the horizontal and moment bearing capacity of four bucket foundation.