The wind generator speeder is the most important transmission system of the wind power system. This paper, with the wind generator speeder in design as a target, studies modeling of the transmission of its planetary gears and precise assembly, and achieves the secondary development of gears and other components based on Solidworks, a three-dimensional modeling software, as well as finishing modeling and virtual assembly of the speeder. Furthermore, the analysis of the planetary transmission mechanism is carried on, and the wind generator speeder's visual simulation is accomplished.