The concept of data as a new factor of production is a significant theoretical innovation put forward by China, based on a precise understanding and prediction of global technological development trends. With the market-oriented allocation reform of data elements as the main line, cultivating a national integrated data market to promote data utilization is the general program for the innovative development of China's data elements. It introduces the fundamental theory of a data field and examines key technologies such as cross-domain data management, data encapsulation, low-entropy data circulation, penetration security, and fusion processing technology. Moreover, the study analyzes engineering practice cases of data fields in health scenarios, proposes innovative application scenarios and engineering practice paradigms for data fields, and looks forward to the prospects in the fundamental theory, key technologies, engineering practices, and ecological construction of data fields, aiming to provide theoretical and practice guidance for data field development and support the modernization of the digital economy and social governance.