View of the shortcomings of the traditional lubrication system design,a design method based on Flowmaster software is put forward. Taking a certain type of wind turbine gearbox as an example,the power loss and the amount of oil supply are calculated,the lubrication system is simulated and the design is optimized.The experimental test of the lubrication system is carried out,which proved the validity of the lubrication system. The results show that,by using the Flowmaster software to design the wind turbine gearbox,the accurate control of flow and pressure can be achieved. When design the system,it must be noted that the temperature variety has a big effect to the gearbox oil pressure.