Although the RV reducer has a series of advantages,such as small size, light weight, stable transmission, long life and high transmission efficiency, but the contact stress between the cycloid and the gear teeth is relatively large and the wear is serious. In order to optimize the structure, the maximum contact stress and the quality is considered as the goal of optimization to reach a small magnitude, with the distribution radius of wheel, short width coefficient, radius of the pin wheel, thickness of cycloid pin gear as optimization variable. Two methods, the genetic algorithm and fmincon nonlinear optimization method, are used. The results obtained by the two optimization methods are consistent, and both have obvious optimization effects, but they lead to the increase of another optimization objective. In order to make the two optimization objectives get better optimization results both, fgoalattain multiobjective algorithm is used to optimize the multiobjective.