In order to solve the problem that the measurement accuracy of machine end motion trajectory fluctuates greatly and cannot meet the actual requirements of the project, a variable structure parameter adjustment model was proposed, and a robot end motion detection system for robot polishing was developed. Based on the axis convergence model, the influence law of key structural parameters such as baseline distance, optical axis angle, vertical field angle on the measurement accuracy in the binocular vision system was studied and the optimal domain of parameters was determined. Through experiments, the interactive influence law of each structure parameter on measurement accuracy was obtained, and the variable structure parameter adjustment model was established. A set of robot end motion detection system was developed, and its accuracy and performance were compared and verified. The verification results show that the detection accuracy of the designed robot end motion detection system is within 0.094 mm under largescale conditions, which is comparable to the accuracy of the laser tracker. It meets the requirements of robot polishing