The tooth surface equations of face gear were derived by coordinate transformation based on the principles of gear meshing and face gear manufacturing process. The face gear drives point contact model was constructed under the circumstances of various individual aLignment errors and coupLing aLignment errors, through numerical analysis and computer simulation, the influence of various errors of aLignment on transmission errors and the shift of bearing contact were simulated, and the corresponding contact path, contact elLipse and transmission error were obtained. Investigation has provided a theoretical reference for design of high-performance transmission, high-quaLity adjustment and installation of face gear drives.