Introduction  In order to implement the "Notice on Accelerating the Digital Transformation of State-owned Enterprises" issued by the State-owned Assets Supervision and Administration Commission, state-owned enterprises are facing the pressure and challenge of digital transformation. Many power engineering enterprises are exploring the direction of digital transformation, and it is an important prerequisite to solve the management of engineering project life cycle data by using digital technologies such as cloud computing, big data, Internet of Things, mobile Internet, artificial intelligence.

  Method  In view of the large volume, diversity and complexity of the whole life cycle data of power engineering projects, this paper analyzed the inapplicability of relational databases in most scenarios, and used the MongoDB, the NoSQL database, to solve the problems of large volume, diversity and complexity of data.

  Result  The author designs and constructs engineering big data platform using MongoDB as the core database, which realizes the flexible modeling and management of the process data of power engineering projects, and serves as the data base of the digital products in the whole process of the engineering project.

  Conclusion  The research has proved that MongoDB database is more suitable for scenarios with large data volume, data diversity, and complexity than relational database, with higher storage efficiency and stronger data query and statistical capabilities in practical applications.