Abstract: Two RV reducer fatigue test benches lubricated by two different greases were used to study the influence of greases on the fatigue life of RV reducer. The results showed that excellent chemical and structure stability of greases were beneficial to retain consistency and viscosity of greases after prolonged working, which played an important role in frictional properties of greases; excellent frictional properties of greases could reduce wear and extend the fatigue life of RV reducer. The study results had great significance to the lubrication design and the monitoring of operation status in industrial robots.