Abstract: A stop valve is provided. A stop valve includes a valve body, a valve core and a connecting block. The valve body is provided with a first opening and a second opening. The valve core is movable in the valve body to communicate the first opening with the second opening and cut off a communication therebetween. One end of the connecting block is located outside the valve body, the other end thereof is fixedly connected to an end of the valve body. A part of the valve core extends into the connecting block and is in threaded fit with the connecting block. The connecting block extends towards the valve body to define a seal portion along an axis of the valve core. When the stop valve is in a fully opened state, the valve core is capable of abutting against the seal portion and forming a linear seal therewith.