The invention discloses a manufacturing technology for an ultra-large split ring piece. The manufacturing technology comprises the steps that the number, size and allowance design of a whole ring piece and the manufacturing technology of the whole ring piece are determined according to the subsection number, cross section characteristics and detection requirements of the ultra-large split ring piece, lifting technology excess materials and other elements, the whole ring piece is cut according to the designed number of split ring sections and then subjected to shaping machining through a special tool, the shaped ultra-large ring sections are marked out according to the finally designed ring section shape and size and then subjected to cutting machining, and finally, the cut ring sections are machined according to the size and shape of a final product. In this way, through the manufacturing technology for the ultra-large split ring piece, the split ring piece with the any split ring section number and the ultra-large diameter can be manufactured, the allowance design and production efficiency are better than those of a traditional free forging technology, limitation to the equipment is small, and the manufacturing technology has the advantages of being obvious low in cost, high in efficiency and capable of being easily applied and popularized to existing common ring rolling equipment, and is suitable for production of various ultra-large split ring piece products.