Considering offshore wind turbines may be affected by ice load, random ice force model was added to wind turbine model and wave action was simulated by using Morison equation. In order to assess the risk of wind turbine system operation, multi-body dynamics model was established with sea ice action to conduct dynamic characteristics analysis of wind turbine under multi-field coupling. The results show that tower displacement fluctuations are mainly affected by wind load. Wave or ice can directly impact tower foundation load performance, making tower continuously vibrate and causing fatigue damage. When wind and ice come together, tower vibration becomes more intense. Since sea ice's continuous strike makes tower foundation load generally greater than that without sea ice case, the design of wind turbine for ice conditions should be corrected and improved.