This study investigated and analyzed the status of difficult patrons, and examined the most effective response measures targeted the public libraries in Busan. A survey on 128 people who served to the public libraries in Busan carried out for analysis of problem behaviors of public library users, and brainstorming and AHP method by 9 librarians for seeking of the effective response plan. This study shows that the most effective response ways for difficult patrons is to enact detailed regulations and the appropriate notification and education to the users about the regulations. In addition, education for communication skills to library staffs should be conducted on a regular basis, like as using positive language, listening techniques, the appropriate response techniques with angry users.