Sealing assembly flexible to rotate and reliable to seal for abdominocentesis instrument

The invention discloses a sealing assembly flexible to rotate and reliable to seal for an abdominocentesis instrument, and belongs to the field of medical puncture instruments. The sealing assembly comprises an upper cover, a lower cover, a choke valve and a movable guard. The gradient of the valve wall of the choke valve is gradually decreased from an opening in the center of the valve wall to the periphery of the valve wall. A sealing lip in the opening in the center of the valve wall is of a trumpet-shaped outward turning structure, and a plurality of small convex ribs extending along the axis of the center of the sealing lip are evenly distributed on the trumpet-shaped outward turning structure of the sealing lip; the movable guard covers the outer side of the choke valve so that the choke valve can perform relative rolling motion on the lower cover along with the movable guard. The sealing performance of the sealing assembly is better, the choke valve is not likely to be turned upwards, and the air leaka