This system is a visual positioning system, which consists of three parts: a 3D binocular camera, a marking plate of electric tightening tool and software.It realizes real-time positioning and tracking of the marking plate installed on the electric tightening tool, calculates the position of the marking plate of the electric tightening tool and the direction of the electric tightening tool, and automatically maps the position of the tool output head according to the structure of the tool itself.