Abstract: With the application of a new type of nanofluid coolant in wind turbine generator set cooling system, the influence of the nanofluid coolant on the power generation efficiency and heat dissipation efficiency of the wind turbine generator set was researched. Results show that, with the application of nanofluid coolant compared with domestic coolant, the power generation efficiency is increased by 4.9% to 6.2%, and the heat dissipation rate is increased by 10% to 27%. Within the allowable range of the total heat exchange capacity, the method of changing nanofluid coolant can obtain the same cooling effect as increasing the heat dissipation area of the heat exchanger. Through utilizing the high thermal conductivity, low corrosion rate, and high boiling point characteristics of nanofluids, the power generation efficiency can be increased and the equipment maintenance costs can be reduced. This technology has a practical application and is feasible.