Gear transmission is one of the most important and widely used equipment in mechanical transmission. To a certain extent, The technical level, design ability and manufacturing level of gears are important symbols to measure the industrialization level of a country. Cycloid gear drive is a kind of wide applications of gear transmission which is studied and developed actively in the world. A new type of cycloid drive is called Output-Pin-Wheel, and it has been obtained through structural innovation. It has lots of advantages, such as small in size, light in weight, large transmission ratio range, high transmission efficiency, stable transmission, low noise, reliable operation, long service life and so on, which make it possible to be widely used in various industrial fields. Although at present, it has a set of more mature design method, This paper does development for Creo based on Microsoft Visual Studio 2005 platform and uses FEA to solve those problems, for the purposes of improving design efficiency and shortening design cycle. The development system has a friendly man-machine interaction interface, so the fast interactive parametric modeling and analysis of main components of reducer can be implemented by using this method, such as cycloid gear, pin-wheel, eccentric shaft, bearings, input shaft etc. On the base of parametric model of reducer, the finite elements contact analysis between the cycloid gear and pins wheel was done by ANSYS software for further research. The results of displacement, stress, strain and contact pressure distribution were obtained. and a set of optimized parameters were obtained also. By optimizing parameters such as eccentricity and pin sleeve radius, the contact stress of gears is reduced by 31.2%, and the transmission load-carrying capacity is improved.