Abstract: Two basic tools of dimensional synthesis are geometric construction and analytical calculation, but there are fewer available number of prescribed positions for dimensional synthesis, and analytical calculation is quite complicated and far from straightforward. In the case of CAD geometric approach, for more than ten prescribed positions, first using the geometric constraints and dimension driving techniques, a primary simulation mechanism is created. After that, based on the different tasks of path and motion generation for the dimensional synthesis, the simulation mechanisms of approximate path and motion generator with Stephenson six-bar linkage are developed from the primary simulation mechanism. The results of computer simulation show that the mechanism simulation approach is not only fairly quick and straightforward, but also has the advantages of accuracy and repeatability.