This study propose the union cataloging based on wiki cataloging method which guarantee the quality of imported bibliographic data by outsourcing. Wiki cataloging means to improves a quality of union catalog used the cooperation of librarians who have the knowledge and experience to the cataloging. The methods are 1) policy of wiki cataloging 2) development of wiki systems 3) establishment of wiki cataloging rule based on advanced librarian cooperation. Especially, advanced librarian take charge of an 245, 260, 300 fields as basic bibliographical elements, general librarians participate expanded fields.