The invention discloses a special movable joint sealing device which comprises a rigid sealing ring, a pressing plate flange, a sealing gasket, a pressure adjusting flange, a clearance adjusting flange, a flange plate and a connecting plate, wherein the pressing plate flange, the sealing gasket, the pressure adjusting flange, the clearance adjusting flange, the connecting plate and the flange plate are axially fastened and connected in sequence, and the center lines of the pressing plate flange, the sealing gasket, the pressure adjusting flange, the clearance adjusting flange, the connecting plate and the flange plate coincide; and the rigid sealing ring is located in a cavity formed by the sealing gasket and the connecting plate and clings to the surfaces of the sealing gasket and the connecting plate. The special movable joint sealing device has the advantages of simple structure, convenience in clearance adjustment and favorable mobility and sealing property.