Ball valve capable of releasing pressure

The ball valve comprises a valve seat, a ball valve element and a valve rod, the valve seat comprises a middle seat body and two side seat bodies, the two side seat bodies are located on the two sides of the middle seat body, convex lugs are arranged on the middle seat body and the side seat bodies, the middle seat body and the side seat bodies are fixedly connected through bolts, a mounting seat is arranged on the middle seat body, and the ball valve element is arranged on the mounting seat. One end of the valve rod penetrates through the mounting seat and is detachably connected with the ball valve element, the other end of the valve rod is provided with a hand wheel, the ball valve element is located in the middle seat body, and a movable sealing sleeve is arranged in the side seat body. When the ball valve is in a closed state, fluid in the side seat body can pass through the pressure relief hole, so that the pressure relief effect is achieved, and meanwhile, the pressure when the valve is opened can be r