The invention discloses a stress-optimized three-gear umbrella rib of a folding umbrella. The umbrella rib comprises an umbrella rib body. The upper end of the body is provided with a first installation hole for being connected with an upper disc. The portion, close to the lower end, of the middle of the body is provided with a second installation hole for being connected with a four-gear umbrella rib. The lower end of the body is provided with a third installation hole for being connected with a small saddle. The body is formed by folding blank formed through stamping in half along the center line in the length direction. The stress-optimized three-gear umbrella rib is characterized in that the width of the portion, located on the second installation hole area, of the blank is largest, and the width of the other part is small. By changing the shape of the blank for manufacturing the three-gear umbrella rib, the main stress part is appropriately widened, and the sub stress part is appropriately narrowed, so that materials are saved, the overall stress capability of the three-gear umbrella rib is improved, and the fracture problem of the umbrella rib is greatly reduced; in addition, during stamping and discharging, the large end and the small end can be alternately arranged in a left-right mode, width complementing is achieved, and therefore materials can be greatly reduced.