The invention discloses a core fixing cooling radiating system for a rotating shaft, which comprises the rotating shaft, cooling pipe components, a cooling connector component, inner ball-end set screws and O-shaped rings. Each cooling pipe component consists of a cooling pipe flange, a cooling pipe and shaft spacer sleeves, the cooling connector component comprises a flow distributing pipe flange, a red copper pipe, an elbow connection flow distributor, a water inlet pipe connector, a water outlet pipe connector, a large sealing ring and small sealing rings, the rotating shaft is sleeved on outsides of the cooling pipe components, the cooling connector component is sleeved inside the cooling pipe components, and connected with the cooling pipe connectors by internal threads of lower ports of the cooling pipe components, one end of each inner ball-end set screw is arranged in the rotating shaft, the other end of each inner ball-end set screw is disposed in an annular groove of the lower portion of the corresponding cooling pipe component, and the O-shaped rings are mounted in sealing grooves of the lower portions of the cooling pipe components and are arranged among the rotating shaft and the cooling pipe components. The core fixing cooling radiating system is compact in structure and fine in water sealing performance, cooling water can circulate in the rotating shaft in a heat field environment, the temperature of the shaft is reduced, and the service life of the rotating shaft is prolonged.