Abstract: In the design of offshore wind power foundation, the key to ensure the safety and stability of the structures is to analyze the force characteristics and destruction modes of pile-cylinder foundation under composite loading modes. This study is aimed to investigate the destruction modes of pile-cylinder foundation of a 3 MW wind turbine in homogeneous soft clay ground, for which a finite element analysis tool ABAQUS is used to establish the model for simulating the combination of different composite loading modes and a normalized foundation destruction envelope within two-dimensional load space is obtained by using method of load-displacement loading. The results indicate that under the composite loading modes, an appropriate vertical load can be helpful for improving the bearing capacity of the foundation, whereas the synergistic actions of horizontal load and bending moment load can exacerbate the destruction of the foundation. With different loading modes, the pile-cylinder foundation shows a variety of destruction modes. Under V-H and V-M loading modes, for instance, the destruction of the pile-cylinder foundation exhibits the following stages: vertical scoop-shaped destruction, spherical rotation destruction, horizontal wedge sliding and overturning destruction. In contrast, under the H-M loading mode, the destruction mode of the pile-cylinder foundation is more complex and displays 4 stages, including overall rotation, scoop-wedge shaped destruction, horizontal sliding and backward overturning.