The invention discloses an automatic discharge device for treatment and disposal of sludge in cities and towns. The automatic discharge device is technically characterized by comprising a discharge box, wherein the discharge box is provided with a feed port, a guide wheel is arranged below the feed port, a guide wheel shaft is mounted between two end faces of the discharge box, the end, extending out of the discharge box, of the guide wheel shaft is connected with a reduction gearbox through a chain wheel and a chain, and the reduction gearbox is connected with a speed regulation motor through a belt pulley and a belt; the bottom face, located in the rotation direction of the guide wheel, of the discharge box is provided with a discharge port, a movable plate is mounted outside the discharge port, a rack is fixedly connected to the lower surface of the movable plate and meshed with a gear, one end face of a gear shaft is jacked by a fixing shaft which is mounted on a bottom face end plate of the discharge box through a bearing, the other end of the gear shaft is mounted on an opposite bottom face end plate of the discharge box through a bearing, and the part, extending out of the bottom face end plate of the discharge box, of the gear shaft is connected with a speed reduction motor through a chain wheel and a chain. The automatic discharge device achieves the purpose of automatic and efficient discharge, thereby being matched with speed efficiency of sludge treatment and disposal equipment.