With the continuous development of information technology, the university library alliances (ULA) have gradually changed from “entity alliance” in the last century to the “entity body combined with digitizing brain” in the present. In the near future, smart libraries (SL) and cloud service platforms (CSP) will be the real protagonists of the library alliances. In this process, the use of artificial intelligence (AI) and cloud computing (CC) technology will become an important trend. The continuous development of China University Library Alliance (CULA) is the result of using emerging information technology to continuously satisfying the needs of readers. In the era of big data, the analysis of mass document data will become a new topic in the development of ULA, and its service focuses will gradually be transferred from traditional business to document data. With the development of AI and CC, focusing on the intelligent, specialization and individuality of the service is the inevitable trend. This article mainly adopts the research method of comparative library science and historical analysis to explain the important characteristics of different development stages of CULA, to analyze the problems of “entity alliances” and “hybrid alliances”, and then to explain why cloud libraries of big data (BD) and smart libraries will be the mainstream of CULA.