The invention discloses a trocar seal membrane with concave-channel structure. Said seal membrane comprises a proximal opening, a distal aperture, and a sealing wall from the distal aperture extending to the proximal opening, said sealing wall comprising a proximal surface and a distal surface, said distal aperture formed by a sealing-lip for accommodating the inserted instrument and formed a gas-tight seal, said sealing-lip comprising a longitudinal axis and a transverse plane substantially perpendicular to said axis. In the lip-adjacent area, said sealing wall comprises the main rotary-wall and a plurality of concave-channel； each of the concave-channels includes two side sealing-walls, which are defined by both edges and extending laterally outward from the sealing-lip and gradually widening. Said concave-channels have the functions of enlarging hoop circumference, reducing the wrapped area, improving lubrication reliability, increasing the axial tensile stiffness, etc., thereby, greatly reducing the frictional resistance and the stick-slip.
