The purpose of this study was to explore the key success factors for virtual team. According to the results of this study, we provide suggestions to an individual or enterprise for their reference to the future planning of virtual team. There were three methods used in this study: literature review, discussion with experts, and Delphi questionnaires. The questionnaire was drafted after literature review and modified by experts. The three times modified questionnaire was mailed to the Delphi expert group which is composed of fifteen experts who is a virtual team member or who is very knowledgeable on virtual team. According to the analysis results, it is found that the five effective key success factors are : (1) the key factors on the dimension of personality are “activity” and “responsibility” ; (2) “objective management”, “communicate” and “work efficiency/time management” are the most important factors on the dimension of capability ; (3) the key factors on the dimension of interaction are “unselfish knowledge sharing”, “a strong sense of belonging” and “support and back up to each other”; (4) setting the common “goal”, “tactic and vision” and “making the decision” are the most important factors on the dimension of collaboration ; (5) “E-mail” is not only most important tool but also high utility rate of communicate medium.