The invention relates to an electric power information system data management system based on unified dimensional modeling and a method thereof. The system comprises a data dimension attribute pool management module used for managing and maintaining a usable data dimension attribute pool, a data dimension model definition module used for achieving definition of data and description of a data dimension model, and a data management interface service module used for providing a unified data management interface for retrieval, storage and statistic analysis of data to prevent data usage change along with structure change. Due to the fact that data description is achieved by means of a unified data dimension attribute definition table and standardized operation including data retrieval and storage is designed, unified management of complex structure data in an electric power information system is achieved, data retrieval and storage and data interaction between different service systems are facilitated, and a unified data basis is provided for designing and developing a data management tool.