Under dynamic conditions, how to achieve accurate transmission shaft torque measurement data is an important way to evaluate the health status and running state of the transmission shaft. The drive shaft torque measurement is often implemented in harsh environment, such as vibration, high temperature and humidity, and strong electromagnetic. The electrical sensors have problems, such as leakage, electric sparks and difficulty in working in the strong electromagnetic interference environment. To address these issues, this article proposes a torque measurement method based on the extrinsic optical fiber Fabry-Perot interferometry. The working principle of the optical fiber sensor is described, and the installation mode of the sensor is given. The torque test platform of the sensor is established and the performance of the sensor is evaluated. Experimental results show that the sensor sensitivity is (0. 224±0. 06) μm/ Nm, which is in good agreement with the theory. The proposed measurement method has advantages of large dynamic range, high measurement accuracy and real-time speed in the torque measurement of drive shafts.