In order to achieve the accurate measurement of the torque of the climbing gear of the jack-up platform, combining the unique advantages of the Fiber Bragg Grating (FBG) technology, a method of torque measurement is developed. The current research status of the climbing gear torque/load monitoring is analyzed, and the mathematical model of the dual FBG torque sensor is established according to the principle of the torque measurement and FBG sensing technology. The overall design of the climbing gear torque monitoring system is carried out, the elastic element is designed and optimized, the calibration experiment platform of the elastic element is constructed, and the sensor is calibrated. The results show that in the linear interval, the linearity error of the FBG torque sensor is 0.780%FS, the hysteresis error is 2.650%FS and the repeatability error is 1.202%FS. A jack-up platform gearbox prototype testing machine is used to test the climbing gear torque sensor and bending strength. The static sensitivity of the sensor is 0.92pm/t and the dynamic sensitivity is 1.02pm/t. The test results basically meets the requirements of stability, reliability, high precision and anti-electromagnetic interference for torque measurement.