Owing to manufacture difficulty, cycloid gears are not widely used in the practical application. The purpose of this paper is to make double-circular-arc modified cycloid epicyclical gear train apply to power transmission system which has the high contact strength and the high lifetime. Double-circular-arc modified cycloid gear epicyclical train is studied in this paper, whose transmission characteristics are analyzed. Based on UG/NX operating platform, 3D parameterization models of gear train are established. The simulation analysis of contact stress is carried on in the circumstance of UG/NASTRAN. Finally, the simulation result is compared with theoretical calculation, so the validity of simulation is verified. Based on the CAD/CAE integration feature of the UG, the parameterization model of the train is built and analysis of contact stress is carried on, which will be used for the optimum design of the gear train. And the theoretical basis is provided for improving the design efficiency, transmission performance and product quality in practical gears manufacturing.