The RV reducer (one tpye of cycloid reducer) which has two stage transmissions is widely used in manyfields of engineering. This project is going to design the first stage of the RV reducer, as well as therelated components. The details contain design of input shaft, planetary gears, output shaft, generalbearings and eccentric bearings. The fatigue analysis is mostly used in the calculation process becausethe fatigue failure happens frequently in such rotation machine. In the same time, the general bearingsdesign is based on SKF General Catalogue and the eccentric bearings design is supported by theChinese standard.