The utility model relates to a ventilating fan for motor coach, mainly comprising a cover board, a blade wheel, an afflux ring, a shell, a motor, a bracket and a baffle ring. The blade wheel takes a centrifuge blade wheel which is directly driven by the motor. The distance between the cover board and one end of the shell is fixed through a positioning ring to form an air outlet of the ventilating fan for motor coach. The afflux ring is used as an air inlet of the ventilating fan for motor coach. The afflux ring is connected with the other end of the shell. The ventilating fan for motor coach is connected with the top of the carriage through a bolt. A rain proof cover is arranged on the top of the carriage through a bolt. When feed the carriage with air, the air inlet of the ventilating fan for motor coach is upward; and the rain proof cover is fixed with the afflux ring through the positioning ring. When exhaust the air from the carriage, the air inlet of the ventilating fan for motor coach is downward; and the rain proof cover is fixed on the cover board through the positioning ring and the bolt at the time.