This study was conducted to analyze the characteristics of the artificial intelligence chatbot service of the library and compare the usability of the chatbot service applied to the library, and to propose a plan to improve the usability of the artificial intelligence chatbot service in the library. In order to achieve this research purpose, usability comparison factors were extracted through previous studies on the usability evaluation of artificial intelligence chatbot services, and based on case studies, artificial intelligence chatbot services applied to libraries were classified into their own website-based and SNS-based chatbot services according to the platform. Experiments, questionnaires, and interviews were conducted to evaluate the usability of website-based and SNS-based chatbot services applied to the library. Based on the results of the usability evaluation, implications and improvement plans for the artificial intelligence chatbot service of the library were derived.