In a highly dynamic environment with numerous information service institutions, continuous changes in information technology, and constantly changing user needs and preferences, public libraries still have confusion caused by broad service content and fuzzy service boundaries. The concept of representational space helps public libraries analyze the foundation of their existence and highlight their position in the development of the country and society. According to the historical background of the development of public library and its significance and value to be conveyed, it represents fairness, memory and modernity in concept, function and form, and in the era of digital civilization, these three representations of public library will also have new development trends.