A dual-camera vision 3D coordinate measuring system using a probe is proposed to solve the problem of the low measuring repeatability about similar system with one camera. It mainly consists of a specially designed optical bar, two orthogonally placed CCD cameras and a computer. In the dissertation, the dual-camera model is established based on the principle of redundancy and the single camera system model. And the analytical equations of the measured point’s coordinates are derived. A test device is built using the easiest three-point model light bar. The experimental result shows that the system with linear points and dual cameras has achieved a measuring stability precision of 0.2 mm and measuring precision of ±0.15 mm in the direction of every axis for a distance of 1 500 mm away from dual-camera system.