A manufacturing method and structure of a carbon fiber rim is revealed. A metal strip is formed by heating a metal substrate to a moldable temperature and then extruded molding. The metal strip comprises two side walls, a connecting wall and an inner rim wall to form a space surrounded by the side walls, the connecting wall, and the inner rim wall. Next, two terminals of the strip are connected to form a circle as a rim frame's embryo. The two side walls, or the two side walls and the inner rim wall of the rim frame's embryo are milled to form plural through holes and become a rim frame. Afterwards, the surface of the rim frame is roughened and covered with a trimmed carbon fiber cloth having a predetermined shape. After heatsetting and surface treating, a carbon fiber rim having a light weight and a strong structure is obtained.