Abstract: In order to reduce the maintenance cost of wind farms,this paper proposes a combination maintenance strategy for wind turbine components of wind farms.On the basis of the Weibull distribution of the failure rate of each component,the optimal preventive maintenance cycle of each component is determined,and then the implementation time of subsequent preventive maintenance of each component is calculated.All maintenance tasks in the future will be combined into multiple maintenance groups in a grouping scheme.All maintenance tasks included in a single maintenance group are arranged to multiple maintenance teams on basis of a hierarchical optimization method in order to minimize the maintenance time so that the downtime of the wind turbine is shortest.Comparing the maintenance cost of the combined maintenance strategy and the preventive maintenance strategy,taking the grouping scheme saving the maintenance cost as the fitness,the optimal grouping scheme is solved by using the genetic algorithm..The simulation results verify that the strategy can effectively reduce the downtime of wind turbines and reduce the maintenance cost of wind farms.