The invention discloses a support system for an end die of a factory-prefabricated immersed tube. The support system comprises a load-carrying frame, an end die plate, a regulating component and a supporting component, wherein the load-carrying frame comprises a plurality of vertical ribs and a plurality of transverse ribs which are arranged in a staggered manner; all the vertical ribs are connected with a bottom die and a top die of a pipe section; all the transverse ribs are connected with a side die of the pipe section; the end die plate is matched with the end part of the pipe section in shape and used for forming of the end part of the pipe section; the regulating component is connected with each of the load-carrying frame and the end die plate and used for regulating the distance between the end die plate and the load-carrying frame; the supporting component comprises a plurality of supporting rods; one end of part of the supporting rods is connected with the foundation, and the other ends of part of the supporting rods are connected to the bottoms of the vertical ribs; and one end of the rest of the supporting rods is connected with the top die, and the other ends of the rest of the supporting rods are connected to the tops of the vertical ribs. With the adoption of the support system for the end die of the factory-prefabricated immersed tube, a lateral pressure borne by the end die plate is transmitted to the foundation, the top die and the side die, the supporting safety and stability of the end die plate are ensured, the mounting and regulating convenience is ensured, the end die plate can be regulated accurately during the construction process, the requirement of the pipe section on high precision prefabricated construction is met, and quality and construction safety risks are reduced.