This article first describes and analyzes resource co-construction and sharing for the China Academic Digital Associative Library (CADAL). Then, an Analytic Hierarchy Process (AHP) model is built to online evaluate the service quality of a digital library (DL). CADAL resource co-construction and sharing can be improved through multi-universities cooperation, and crowdsourcing can be used for collaborative CADAL development. The AHP model was found to be effective in evaluating and controlling the service quality of a DL. CADAL’s characteristic is that digital technology is used to make ancient books into electronic books, to let these books be freely read. This study could be helpful to librarians interested in resource sharing and ancient book using. In addition, the automatic computer tag classification for the construction of a digital book has significant reference value. © 2018, Published with license by Taylor & Francis Group, LLC. © 2018, © 2018 Xi Qingkui, Hu Wenliang, Li Xinquan, Qian Zhang and Ni Feng.