The integration and service of digital archive resources is a new area to explore in the archive field. In order to solve the problems emerged in practice, this paper adopted the methods including literature review, focus group for data collection, Straussian Grounded Theory for data analysis. Based on the field research from 104 institutions (municipal archives, governmental information resource management centers, and big data centers etc.), this paper identified the types of tacit knowledge in process of archival practice activities, analysed the empowering role of these tacit knowledge in the process of digital archives resources integration and service, then therefore, enabled the development of a classification of these tacit knowledge.