Ventilation butterfly valve

The utility model provides a ventilation butterfly valve which comprises a valve body, a rotating shaft is installed in the valve body, a butterfly valve driving device is installed at the upper end of the rotating shaft, and a valve plate is fixed to the rotating shaft. The bottom end of the rotating shaft extends out of the valve body and is provided with a mechanical pointer, the mechanical pointer comprises a fixed disc, a connecting column, a thick pointer and a thin pointer, the fixed disc is fixed on the valve body, the connecting column is fixedly connected with the rotating shaft, andthe lower side of the connecting column extends out of a through hole in the fixed disc; the thick pointer and the valve plate are the same in direction, the end of the thick pointer horizontally extends out of the fixing disc, and the thick pointer can rotate along with the rotating shaft; an arc-shaped finger needle hole is formed in the fixing disc, the finger needle hole and the connecting column are coaxial, a row o