To address the problems of low maintenance efficiency, difficulty in predicting maintenance timing, and high maintenance cost proportions in wind turbines, this paper proposes a combined maintenance strategy for wind turbines based on random shocks and multi-state degradation. Considering the effects of multiple state degradation and random shocks during wind turbine operation, the degradation process is first modeled using semi-Markov process and random shock model. Second, a multi-state combined maintenance strategy is developed, in which the degradation states of wind turbines are clarifies into normal, opportunistic maintenance, preventive maintenance, and corrective maintenance zones. Preventive maintenance, opportunistic maintenance, and corrective maintenance are jointly applied in maintenance decision-making to determine the maintenance needs of each wind turbine component, along with appropriate inspection intervals and maintenance thresholds. Simulation results show that the proposed strategy effectively reduces operation and maintenance costs of wind farms while improving the operational reliability of wind turbines.