Abstract: In order to improve the design efficiency and shorten development period of transplanting mechanism, 3D parametric design system of the transplanting mechanism was built in this paper .Based on backward rotary transplanting mechanism with eccentric gears and non-circular gear, 3D Software UG6.0 was chosen as design platform and UG secondary development technology of NX Open for.NET was adopted in the system. 3D models of the parts and assembly of the transplanting mechanism, which includes 3D model of non-circular gear, can be easily created if users input the main design parameters of the transplanting mechanism by user interface of the system, and 3D parametric design of the transplanting mechanism can be realized.