Abstract: To address the vibration issues encountered during the operation of RV reducers, current research primarily focuses on cycloidal wheel modifications, with limited consideration of the impact that involute gear modifications have on RV reducer vibration. This study takes the RV-20E model as a subject to examine the influence of modifications on both involute gears and cycloidal wheels on the vibration characteristics of the reducer. Parametric models of pre- and post-modification planetary gears and cycloidal wheels were developed in Solidworks, resulting in a total of five complete parametric models of the RV-20E reducer. These models were then imported into Ansys for modal simulation to verify that resonance does not occur under normal operating conditions. Subsequently, dynamic simulations were conducted, using the pin gear housing as the evaluation point. The vibration response of the RV reducer was analyzed based on the time-domain and frequency-domain vibration signals at this point, and the simulation results were validated through experimental testing. The findings indicate that with involute gear profile modifications alone, the root mean square of the RV reducer’s vibration acceleration was reduced by 14.79%. When both stages of modifications were considered, the root mean square of vibration acceleration decreased by 31.69%.