Abstract: Based on the process of the nuclear power operation and maintenance, this paper overviews various operation and maintenance data in detail, analyzes the data types, data characteristics and magnitude, and then puts forward a data management framework between big data and relational data; Based on the business characteristics of the remote operation and maintenance, the data management requirements of nuclear power operation and maintenance are further analyzed; With the B/S framework, a data management system based on the integration of big data and relational data is developed, and the management mode of the nuclear power operation and maintenance data is innovated; The system has been effectively applied in the operation and maintenance service, which greatly improving the efficiency of the nuclear power operation and maintenance, and also providing the foundation for the follow-up research of the intelligent operation and maintenance.