The utility model discloses a warm wind window structure of a hydro-generator. The structure mainly includes an enclosed cylindrical structure formed by a warm wind window frame, a warm wind window and a door. The warm wind window frame is welded on the outer wall of a stator base. The warm wind window and the warm wind window frame, and warm wind windows are fitted together through bolts and fine felts are arranged between the fitting faces. In the warm wind window, through arrangement of an opening above a base wall or an air cooler support, hot air is introduced to a turbine chamber or a hydro generator chamber and fresh air is supplemented to an opening in a hydro-generator pit wall so as to ensure the air pressure balance in the hydro-generator pit so as to maintain stable operation of a generator set. The warm wind window structure is simple and practical and is a utility model structure which carries out second use of exhaust gas loss of a generator.