A technique to calibrate faro retro probe using laser tracker system (LTS) is presented. The deep-access retro probe enables LTS to perform three-dimensional (3D) measurements of surface hidden features. It has been shown that misalignment errors are the key contributor to measuring errors of retro probe. A device for measuring misalignment errors of retro probe is invented. Theoretical analysis and experiment show that using this technique to calibrate retro probe, the misalignment errors of retro probe can be eliminated effectively and quickly.