Disclosed is a valve, comprising a valve body, an inner valve seat and a valve core. The valve core is mounted in the valve body. The inner valve seat is mounted in the valve body. The inner valve seat has a annular body and a seal structure extending inwards from an inner peripheral surface of the annular body, wherein the seal structure is arranged in such a manner that the seal structure seals a gap formed among the valve body, the inner valve seat and the valve core when the valve is in a closed state. After the valve is used for discharging liquid, the amount of liquid residue inside the valve can be greatly reduced.