<p>Disclosed is an overflow protection valve, comprising a valve body (1); a valve chamber formed within the valve body (1); a water-inlet (2) and a water outlet (3) respectively provided at both sides of the valve body (1); an on/off switch component (4) provided at the water-inlet within the valve chamber; and a flow guide post (5) hermetically connected with the on/off switch component (4), with the interior of the flow guide post (5) being in communication with the water-inlet (2) via the on/off switch component. A first stage water-outlet (6) and a second stage water-outlet (7) are provided on the flow guide post (5) in the direction of the water flow; a sliding sleeve (8) is provided outside the flow guide post (5); and a plug (81) able to seal the water-outlet (3) is hermetically provided at the top of the sliding sleeve (8). The central part of the sliding sleeve (8) is a sliding wall (82) hermetically fitted on the outside of the flow guide post; a water flow passage (9) is formed between the sliding wall (82) and the inner wall of the valve body (1); a water-outlet hole (83) is provided on the sliding wall (82) and is able to communicate with the second stage water-outlet (7) when the sliding wall is moved up and down; a bottom shoulder (84) of the sliding sleeve (8) is connected with the outer wall of the flow guide post (5) and the inner wall of the valve body (1); an elastic component is provided on the bottom shoulder (84) to provide pressure thereon; and a chamber (11) in communication with the first stage water-outlet (6) is provided below the bottom shoulder (84). The technical problem of overflow protection valves in the prior art not being applicable to control water flow is solved by the present overflow protection valve.</p>
