The power engineering cost information database is an important technical foundation for the digital development of power engineering cost management, the establishment of power carbon accounts, and low-carbon transformation. The application of big data technology can provide users with more intuitive and effective functions for the database. This article introduces the main differences in cost information between power engineering and general civil construction engineering, briefly distinguishes the cost information of power engineering, and studies in detail the application directions of power engineering cost information databases in data collection and integration, mining and prediction, risk identification, and engineering cost analysis.