Abstract: The offshore wind turbines are prone to resonance damage under the random dynamic loads, such as the wind and waves, due to their complex environment. In order to study the vibration characteristics of the offshore wind turbine, the reasonable design parameters are selected; and the whole model is built by use of ABAQUS software, considering offshore wind turbine and pile-cylinder composite foundation. The modal analysis is carried out by Block Lanczos method. The self-vibration frequency of the wind turbine system and the external load frequency are compared with each other. The influencing factors of the whole vibration characteristics of the wind turbine are analyzed, including the foundation type and the restraint conditions. The results show that the first and second order bending vibration frequency and the third order torsional vibration frequency are the main resonance frequency of the wind turbine. Compared with the single pile foundation, the pile-cylinder composite foundation can effectively improve the ability to resist horizontal loads. With the design parameters in this paper, the wind turbine can avoid the occurrence of resonance. The influence of pile-soil interaction (PSI) should be considered in the pile foundation design of wind turbines.