VoIP service is steadily growing due to the spread of smartphones, enhanced network, and various VoIP applications. But, VoIP has many security vulnerabilities because it is based on IP network. This paper analyzes the important weight of VoIP security checklists for incident prevention and response using AHP. The results of AHP analysis showed that network security, incident response, and access control were the most important in technical, administrative, physical standpoint. This study proposes factor analysis of VoIP security checklist at first time. By doing this, it will be used helpfully when VoIP service providers establish their own security policies and inspect their VoIP environment according to their security policies.