With the rapid improvement of China's economic level and the rapid pace of modern social life，the general public's amateur cultural life is increasingly characterized by individuality and fragmentation.As an important public cultural place for collecting and disseminating human civilization of knowledge and promoting social development and progress，public libraries face new problems and tasks：in the new era of information technology and 5G mobile network，how to use the modern technology to play its role as part of the socialist public cultural service system，so as to better adapt to and meet the needs of people for the good spiritual and cultural life.Based on the case of the development and innovation of the Hantai District Library in Shaanxi Province under the Internet background，this paper actively explores the use of the Internet to expand and enhance the public cultural service mode and quality effect，hoping to make useful explorations for the library construction in the new era.