The invention discloses a mounting jaw of a wire clamp belonging to the technical field of jaws. The mounting jaw comprises a mounting plate, wherein the top of a front wall of the mounting plate is connected with a fixed top plate; a first sliding chute is longitudinally formed in the front wall of the mounting plate; a movable top plate is arranged on the front wall of the first sliding chute; the bottom of the movable top plate is connected with a bearing block; the bottom of the bearing block is provided with a lead screw through a bearing; the bottom end of the mounting plate is connectedwith an adjusting device housing; an adjusting button is inserted into the left side wall of the adjusting device housing; the right end of the adjusting button is connected with a guide rod; the guide rod coats the outer side of the lead screw; the right end of the guide rod is connected with an adjusting plate; and an outer thread matched with the lead screw is arranged on the left side wall ofthe adjusting plate. The mounting jaw of the wire clamp is convenient to use, is capable of clamping, stretching and fastening a wire, and is capable of adjusting the tightness while carrying out operation, so that the mounting effect is relatively good.