Automatic flushing cistern

The utility model relates to an automatic flushing cistern which comprises a cistern body, a drainage pipe and a drainage valve. The drainage pipe is used for draining water in the cistern body, the drainage valve is mounted at the inner end of the drainage pipe and used for controlling the water in the cistern body to enter the drainage pipe, a working chamber is arranged on the drainage valve and used for enabling the drainage valve to be in the open/close state by the action of the water pressing a valve core when the water flows in and relieving the pressure of the water on the valve core to enable the drainage valve to be in the close state when the water flows out, and a drainage structure used for the water to flow into and flow out of the working chamber is arranged on the drainage valve. The automatic flushing cistern is characterized in that the drainage structure comprises a two-way water pump capable of discharging the water in the working chamber and filling water into the working chamber, and th