According to the problem that mechanical precision and assembly technology cannot meet the application demands when a couple of fibers non-contact dynamic connected each other, this article analyzes the coupling error of optical fiber rotate connector. Based on analyzing the trace of fiber collimator, it is established an insertion loss and coupling efficiency theory model that analyze the discipline in aspect of radial deviation, axial deviation and angular deviation. This research obtains the effect discipline of the three errors on transmission loss of optical path through experimental data. With the result that the sensitivity sequence from big to small of coupling error of fiber collimator is angular deviation, radial deviation and axial deviation. The researches accomplish the rotary connection of optic fiber and provide the theoretical basis of developing of single and multi channel fiber optic rotary connectors.