In order to study the correlation of vibration characteristics of RV-40E reducer and analyze the characteristic frequency of vibration signals, the RV reducer was tested at constant speed, increasing speed and decreasing speed by using the comprehensive test platform of precision reducer, and the vibration signals at different speeds were collected. Through data processing with MATLAB, the frequency domain analysis and autocorrelation analysis of vibration signals at each speed are carried out. It is found that the autocorrelation of RV reducer increases with the increase of rotating speed. The autocorrelation does not have periodicity in the process of deceleration and acceleration. The meshing frequency of the primary and secondary drives has a great influence on the operation of the reducer. This study can provide an effective means for fault diagnosis of RV Reducer.