Abstract: At present, some nuclear power plants in China have been operating safely for more than 10 years, entering the middle stage of operation life. A lot of operational experience and data is accumulated for the system and equipment. The existing safety valve maintenance policy is based on the early design experience and the analysis assumptions of PSA（ probabilistic safety assessment）. These assumptions do not reflect the actual operational experience and feedback of the operating nuclear power plants. The reliability of these equipment is increased with the current technological developments. In this paper, the reliability-centered maintenance（RCM） method is used to optimize the maintenance policy of these safety valves.