The invention discloses a check valve, which comprises a valve body and a valve core, wherein a top plate is arranged at the inner top of the valve body, a bottom plate is arranged at the inner bottomof the valve body, the valve core is located between the top plate and the bottom plate, reinforcing ribs are inserted into the valve core, the bottom plate is in an L shape integrally, a ferromagnetic coil and a lock pin are arranged inside the bottom plate, the lock pin can slide up and down inside the bottom plate, a lock hole, corresponding the lock pin, is formed at the bottom of the valve core, a base is arranged at the bottom of the bottom plate of the valve body, a start button is arranged on the left side of the base, and a push rod and a knob are arranged in the middle of the base.The check valve has the advantages that the ferromagnetic coil inside the bottom plate can attract the valve core and the base closely according to the electromagnetic attraction principle, and cooperate with the lock pin on the bottom plate to further improve the sealing performance of the valve body.