In order to study the main parts of RV reducer and the natural frequency of the whole machine, to avoid resonance when the excitation frequency is close to that of RV reducer. Taking RV-320E gear reducer as the research object, the software Pro/E is applied to carry out 3D modeling of RV gear reducer parts and complete the assembly of the whole machine. Import the built model into ANSYS Workbench for finite element modal analysis, calculate the first ten order natural frequencies of the main parts and the whole machine, and then compare with the excitation frequencies of RV reducer to find out the parts that may resonate. Research shows that: When the motor speed is 1500r/min, the excitation frequency is difficult to cause the resonance of the parts and the whole machine in RV reducer. However, there is a close natural frequency between the cycloid wheel and the whole machine, by changing the cycloid gear material to avoid the inherent frequency and resonance.