The 16th Advanced Digital Library Seminar was held in Chengdu in October 2019. The subject of the seminar is "Data science, data management and data application". More than 260 librarians, researchers, teachers and students from more than 80 universities and scientific research institutions had attended this seminar. The experts exchanged and discussed the international latest progress and frontier trends of digital library research and service practice in the field of scientific data management and service, and showed the new positioning, mission and development of digital library in the era of open science and scientific big data. This paper discusses and analyzes the current situation and future development prospect of digital library from three aspects: the development trend of scientific big data field under the background of open science, the positioning and challenges of digital library in the field of scientific big data, and the profound change and influence of new technology on library business system. In particular, this paper points out that in the future, library (documentation and information institution) will become a "Integrated cross-border knowledge management and service consulting institution" with the management and service of data knowledge ecosystem as the core.