Abstract: The effect of center distance error of machine tool employed in machining globoidal cam was discussed. Based on the offset surface theory,the equation of the globoidal cam profile and the mathematical model of the profile error were established,and the sensitivity coefficient of the center error was derived. The variation of the sensitivity coefficient corresponded to different tool paths was further investigated. The real profile and profile error were simulated through VC + + and PROE software,and the impact and collision of the globoidal cam mechanism caused by the center distance error and its generation mechanism were revealed.Resultsshow that the center error degrades meshing quality and has a bad influence on the transmission performances.