The sensitivity of the 1-order and 2-order vibration frequency of the wind wheel changing with the working conditions should be found in order to discover the main way of the anti-vibration design of the wind turbine, and how to distinguish the major incentive of the fatigue damage accident and the blade fracture accident. The response curve of the 1-order and the 2-order vibration frequency changing with wind velocity and centrifugal force were found by the numerical modal analysis and the experimental verification of the wind wheel about a small horizontal axis wind turbine based on fluid structure interaction analysis. The results show that the impact of the centrifugal force on the dynamic vibration frequency of the wind wheel was more significant than that of the aerodynamic load, and that the 1-order symmetry vibration frequency should be the most noteworthy parameter in the design of the structural dynamics characteristics of the wind wheel, since it was the most sensitive to change in the working conditions and its trigger was greater than the other stresses of the 1-order and 2-order vibration stress. The study also finds that the growth pattern of the 1-order vibration frequency changing with the aerodynamic load was quadratic, while that of the 2-order vibration frequency was linear.