The invention provides an under-actuated three-arm type non-cooperative target docking-capturing device, relating to a docking-capturing device. The invention solves the problem that: the prior non-cooperative target docking mechanism is easy to collide with satellite spray pipes in a docking process, thereby causing poor docking reliability. An under-actuated manipulator motor (18) is arranged on an upper end face of a lead screw nut plate (2) on a lifting mechanism; an output shaft of the under-actuated manipulator motor (18) is connected with a ball lead screw (23); the ball lead screw (23) is sleeved with a nut (21); a manipulator driving plate (17) is fixed on the nut (21); three manipulators are evenly arranged on a manipulator mounting platform (4); the other ends of three first coupling-connecting rods are respectively in rotary connection with the manipulator driving plate (17); and an umbrella-shaped buffer mechanism is positioned above and flexibly connected with the manipulator mounting platform (4). The docking-capturing device has the advantages of high docking reliability, wide capture enveloping range, few drive elements, simple control, rapid capture, etc.