The invention discloses a machining tool for a metal sealing gasket. The machining tool comprises a stamping cavity, a die cavity, a bearing box and a workbench and further comprises a stamping mechanism, a feeding mechanism and a clamping mechanism, wherein the stamping cavity is formed in the workbench and composed of a top plate and four brackets located on the workbench, the stamping mechanism is located on the top plate, the bottom surface of the workbench is connected with the die cavity, control boxes are arranged on the left side and the right side of the die cavity, a die groove is formed in the die cavity, the upper portion of the die groove is not covered by the workbench, the feeding mechanism and the clamping mechanism are further arranged on the workbench and in the die cavity, the bearing box is arranged below the die cavity, the bearing box communicates with a waste box, a conveying belt is arranged in the waste box, a discharging port is formed in the joint of the conveying belt and the waste box, and universal wheels are connected to the bottom surface of the waste box. According to the invention, automatic feeding of metal plates, stamping machining of sealing gaskets and automatic ejection and taking can be achieved, waste materials are automatically discharged, manpower is saved, and the machining efficiency is improved.