Abstract: With the continuous development of the ancient books protection plan and the digital publishing of the ancient books，China has accumulated a huge number of ancient books digital resources. Under the environment of data intelligence，how to apply new technologies and new ideas to realize the extraction，display，activation and utilization of excellent cultural genes contained in ancient books has gradually become the main goal and core task of ancient books digitalization in the new era. Based on the digitalization of ancient books，this paper puts forward the concept of"digital reconstruction of ancient books"，and analyzes the differences between the two concepts. Then it refines the theoretical basis of digital reconstruction of ancient books，and constructs a stack model from the carrier record layer，content organization layer and application layer.The paper also puts forward the realization approach of digital reconstruction of ancient books from the five dimensions of theory，technology，users，mechanism and mode，which provides a reference for the in-depth development and activation of ancient book resources. Digital reconstruction of ancient books is an important part of the activation of ancient books in the future，which can provide a new guiding concept for the work of ancient books in the new era.

Key words: digital reconstruction of ancient books, smart data, digital humanities, knowledge organization