The four beam laser tracking interferometer system for three-dimensional coordinate measurement is introduced including the principle of measuring system, the redundancy technique, laser tracking interferometer, a new type of target retroreflector, the optimal arrangement of system and the experimental results. The future work is also pointed out. The experimental results show that four beam laser tracking interferometer system has achieved an accuracy of 0.0620 mm on a 700 mm×600 mm plane located 800 mm away from the trackers.