Energy-saving environment-friendly exhaust fan

The invention discloses an energy-saving environment-friendly exhaust fan. The exhaust fan comprises a shell, an air duct is arranged in the shell, a rotating shaft is arranged in the air duct, and abelt groove is formed in the rotating shaft. A plurality of blades are uniformly and fixedly arranged at one end of the rotating shaft, a first motor is arranged on the shell, and a belt wheel is arranged at the output end of the first motor. The belt wheel is connected with the belt groove through a belt, the belt penetrates through the shell, and a baffle is arranged on one side of the rotatingshaft. The baffle is provided with filtering holes, and the two ends of the baffle are each provided with a first fixing plate. A second cavity and two symmetric first cavities are formed in the shell. The exhaust fan has the advantages that the wind power is controlled so that the use power of the first motor can be reduced, and the energy-saving performance of the fan can be improved; and dust which is blown out is disch