The invention provides a clamp for assembling an opening and closing connecting lever. The clamp comprises a bottom frame which is formed through a bottom plate, two side plates and an upper plate in a welding manner, wherein a square hole is formed in the center of the bottom plate; a hollowed-out opening of which the shape is corresponding to that of a shaft sleeve of the connecting lever is formed in the center of the upper plate; a positioning plate with a through hole is fixed to the upper plate and used for positioning a connecting lever frame of the connecting lever during assembling; one end of a screw rod is provided with a nut while the other end of the screw passes through a pressing plate, a punch, the through hole, the hollowed-out opening and the square hole and then is fixed to the bottom part of the bottom frame through a gasket and a screw. The nut can rotate under the effect of external force, and the rotating nut drives the pressing plate to press the punch on which the shaft sleeve is borne to move toward the connecting lever frame of which four corners are correspondingly provided with buffering parts, then the punch runs through the connecting lever frame, the positioning plate and the upper plate and finally falls into the bottom frame, the shaft sleeve is pressed into the connecting lever frame, and the buffering parts are uniformly distributed between the connecting lever frame and the shaft sleeve, so as to finish the assembling of the connecting lever. According to the clamp, a plurality of buffering parts can be uniformly distributed between the connecting lever frame and the shaft sleeve and remain the same distributing height and size, so that the mounting size of the connecting lever can be ensured, and as a result, the performance reliability of the connecting lever is improved.