Abstract: As traditional reference and information services have become inadequate to the readers，this paper aims to study knowledge organization and the construction of knowledge service system in reference and information services.The study suggests that library reference and information services will inevitably develop into knowledge service.The author then discusses the construction of explicit knowledge organization system of FAQ database，information navigation database，questions and answers database，knowledge database，expert database and knowledge map.Construction of tacit knowledge organization system of reference service team and externalization of tacit knowledge are also discussed.

Key words: reference and information service, knowledge service, knowledge organization, digitalized library, library resources utilization, literature retrieval