The invention provides a large-allowance capturing mechanism for an end effector of a spatial large manipulator, relating to a large-allowance capturing mechanism. By the adoption of the large-allowance capturing mechanism for the end effector of the spatial large manipulator, the problems that an end effector mechanism and a control system of an existing spatial large manipulator are complicated and the reliability of space application is lowered are solved. A linear sliding bearing is installed on each linear sliding bearing guide rod in a penetration way; a finger installation platform is connected with the three linear sliding bearing guide rods in a sliding way through the three linear sliding bearings; a nut floating spring is sheathed on the outer wall of a ball screw nut; the center of the finger installation platform is elastically connected with the ball screw nut in a micro floating way through the nut floating spring; one end of each main connecting rod is rotationally connected with the finger installation platform; the other end of each main connecting rod is rotationally connected with a finger; one end of each auxiliary connecting is rotationally connected with the finger installation platform; and the other end of each auxiliary connecting rod is rotationally connected with the finger. The large-allowance capturing mechanism provided by the invention is used for the spatial in-orbit end effector.