Automatic centering clamp

The utility model relates to the field of clamp tools. The utility model provides an automatic centering clamp. The clamp comprises a clamp bottom plate making contact with a machining face. A throughhole used for machining is formed in the middle of the clamp bottom plate, a movable sleeve is arranged above the through hole, the moving direction of the sleeve is perpendicular to the clamp bottomplate, an inner hole of the sleeve and the through hole are coaxially arranged, a plurality of sets of limiting connecting rods are evenly hinged to the outer side of the sleeve, and a telescopic device driving the sleeve to move is fixed to one side of the sleeve. The sleeve is used as a positioning device during machining, automatic centering of the interior of the sleeve and the interior of the sleeve to be machined is achieved through separation and combination of the sleeve and the through hole, the requirements of various machining steps are met, the auxiliary positioning effect can beachieved through downward p