Flush valve and control method thereof

The flush valve comprises a valve body, a piston mechanism and a control device, the valve body is provided with a water storage cavity, a water inlet runner, a water outlet and a piston cavity, the water inlet runner, the water outlet and the piston cavity all communicate with the water storage cavity, the water inlet runner is used for being connected with an external water supply source, and the piston mechanism is arranged in the piston cavity. The piston mechanism comprises a flushing piston and a water control piston, one end of the flushing piston right faces the water outlet, and the control end of the control device is located in the piston cavity. The control method comprises the steps that the position of the water control piston in the movable cavity is adjusted through the control device, so that the water flow direction in the piston cavity is adjusted to control the flushing piston to close or connect the water outlet. According to the flushing device, the path of water flow rushed out of the w