The invention relates to a metal middle frame and a metal middle frame processing method. The metal middle frame processing method comprises the following steps of acquiring a bending section bar, a linear section bar and a middle plate, wherein limiting grooves are formed in the end parts of the bending section bar and the linear section bar; oppositely installing the bending section bar and thelinear section bar end to end on the periphery of the middle plate and forming a metal side frame; acquiring a plurality of limiting buckles, and enabling the limiting buckles to slip along the limiting grooves so as to fix the butt-joint end parts of the bending section bar and the linear section bar adjacent to each other; carrying out groove milling processing in the direction from the butt-joint end parts to the limiting buckles so as to obtain a first-stage groove; and taking the limiting buckles out of the limiting grooves, carrying out injection molding processing on the first-stage groove, and carrying out surface treatment on the metal side frame so as to obtain the metal middle frame with an antenna groove. The metal middle frame processing method is easy to operate and high in stability, the elastic deformation is inhibited, the stability in processing the antenna groove is ensured, and the processed metal middle frame has high yield.