Measurement of the bearing bush temperature in threat bearing and pilot bearing. In view of the special condition in oil tank of hydro turbine, bearing bush temperature sensor is expressly optimized in design. The protector of bellows is fixed on the bottom of sensor probe, which can enhance the protection to cable and prevent the cable from rupturing under the impact of oil flowing. Screw thread with movable cutting sleeve allow that cable doesn't h***e to circumrotate in pace with the probe and the depth of probe's immersion can be adjusted befittingly when RTD is fixed. Sensor element of chip, laser beam wielding technique, antivibration, high stability. Shielded cable is oil-proof and heat-resistance. Sheath layer and insulating layer made of special polymer can service stably in the environment of 50c for 8 years. Core wire plated with sliver h***e a perfect performance in conductivity and static