Currently, the mechanical vehicle generating system is a relatively developed vehicle generating system that is widely used in a variety of places where mobile power supply is in shortage. This paper applies CATIA to process three-dimensional parametric modeling design for the power take-off and transmission of the system, using PROTEL DXP to design and analyze the electronic control part of the system. Firstly, this paper will determine the power taking project that takes power from the fifth gear output shaft gear of the transmission. Secondly, this paper will design and check the parameter of gear with gear transmission method after determining the transmission ratio. And finally the supporting project of gear will be arranged so as to design and check the gear shaft, as well as choosing appropriate bearing and spine.