We studied the problems of large fluctuations in the dynamic friction torque data of lidar shafting and low precision of repeated measurements. The data cloud constructed based on the test spindle control system was fused with the GA-BP algorithm, and a self-updating control algorithm for lidar shafting friction torque detection equipment was proposed. The data cloud was constructed based on the actual speed, ideal speed, speed error and speed error change rate of the test spindle. The density and distance information were used to add and delete data, and the online control parameters were adjusted by the GA-BP algorithm. Taking the lidar shafting friction torque detection equipment to test the main shaft and the measured shaft system as the research object, the simulation experiment proves that this method improves the system’s anti-interference performance compared with the control system using the Z-N-PID algorithm. The friction torque is detected by lidar shafting friction torque detection equipment. The experimental results show that the proposed self-updating control algorithm reduces the average overshoot by 12.77% compared with the Z-N-PID algorithm, the data standard deviation after stability is reduced by 5.00%-40.63%, and the repeated measurement error is reduced by 24.20%-71.66%.