Flat Slab Gate Valve SeatSelf-adjusting structure, characterized by: rectangular grooves are provided at one end near the valve seat of the gate, with rectangular valve seat gaskets embedded within. A T-shaped groove is centrally located near the bottom end of the rectangular groove, housing an O-ring. Therefore, it can adjust the seal between the valve seat gasket and the gate, while also ensuring the seal between the valve seat gasket and the valve seat. The flat gate valve seat structure is simple, scientifically designed, with reliable sealing performance, easy to machine, and can be widely used in various applications.