In order to reduce the overall replacement cost of the main gearbox (growth gearbox) of the doubly fed asynchronous wind turbine and make the operation process more concise，based on WT2000 series wind turbines,a main shaft fixing tooling was designed to replace the role of gearbox and fix the rear end of main shaft.Some new operation processes and methods in the air replacement of WT2000 series wind turbine gearbox were explored and practiced.The results show that the proposed structure greatly reduces the operation cost (including crane cost,time and labor cost) of gearbox replacement of WT2000 series wind turbine,the loss of power generation during maintenance is reduced.