To grasp the cumulative fatigue condition of manufacturing employees and to effectively prevent the happening of overwork as well as safeguarding workers' physical and mental health, we use the latest Cumulative Fatigue Symptoms Index (CFSI) of Japan to carry out the investigation on the fatigue status of employees. We choose a manufacturing company in Wuxi of Jiangsu province as an example. This paper is designed to provide the empirical basis for preventing the overwork in China, explore the applicability of the CFSI in China and provide a basis for developing a fatigue measurement scale suitable for the situation of China.