Abstract: Pose repeatability of robot is very important for robotics research and development. In this paper, a non-contact measurement system (LW-1) for the pose repeatability of robot is presented. Its sensor device consists of six eddy-current sensors and a cubic target which can be mounted on the wrist of an industrial robot. A special mathematical method, the vector properties and screw theory are used to determine the transformation matrix between the sensor and target frame, and to enhance the robustness of the solution. As last, the structure of the sensor device is described and some test results are illustrated. The system(LW-1)is simple in structure and low in cost, and-has given a measurement accuracy of ≤±5μm in displacement and of ≤±16″ in angles on a static test.