The invention provides a device for cleaning and maintaining the interior of a hub in a wind turbine nacelle, belonging to the technical field of wind power equipment. The device comprises a handle component, a switching assembly, a combined cleaning assembly and a maintenance assembly. The switching assembly is connected in a switching shaft block through a switching shaft. A high-temperature steam cleaning mechanism and a negative-pressure contaminant suction mechanism are arranged in the cleaning assembly to remove oil contaminants in the hub in the wind turbine nacelle. The device has a high level of integration, is easy to operate, and can improve the operation stability of a wind turbine.