In response to the need for high-precision micro-torque measurement of the torque fluctuation of the gyroscope motor, a highprecision counter-torque measurement system based on a torque device and an angle sensor is proposed. Based on a coaxially transmitted stepped shaft structure, the external wiring is flexibly connected with spring like hairspring to reduce the elastic interference torque caused by wiring, and realize the high-precision measurement of the torque fluctuation; based on the traditional weight calibration, the static calibration and uncertainty analysis of the measurement system are carried out. The experimental results show that the system measurement accuracy is improved by 90% compared to before optimization. In the range of -10~ 10 mN·m, the measurement accuracy is as high as 0. 06%, the linearity is better than 0. 03%, and the drift error is better than 0. 5 μN·m/ 2 h, the uncertainty is better than 0. 025%.