Bearings are one of most important parts in the rotating mechanisms, which qualities directly influence the performances of machine tools. According to statistics, there are 30 percent of failures in the rotating mechanism to be relative to bearings. So, we must strictly check the quality of bearings before they are sold. Some specific characteristics are desired in an endurance test system to achieve the control requirements of a life test series. An individual test run takes a long time; therefore, the test machine must be capable of running unattended without experiencing variation in the applied test parameters such as load(s), speed, lubrication conditions, and operating temperature.