In order to study the surface integrity of cycloidal wheel of RV reducer,the forming grinding experiment of 20CrMnTi steel cycloidal wheel was carried out.The influence of grinding wheel rotation speed,cycloidal wheel feed speed,grinding depth and grinding wheel particle size on the surface roughness of cycloidal gear were all analyzed.The results show that the grinding wheel particle size has the most significant effect on the surface roughness,followed by wheel rotation speed and feed speed.The grinding wheel with grain size of 150 # was selected to carry out experiments with different grinding parameters.The prediction model of surface roughness of cycloidal gear grinded was obtained.When the grinding wheel speed is 3 200 r/min,the feed speed is 12 m/min and the grinding depth is 012 mm,low surface roughness can be obtained.The prediction model has higher prediction effect.The maximum relative error is only 51%,which provides reference for reasonable selection of grinding parameters in actual processing.