This study is designed for the purpose to provide realistic way for the increasing of organizational citizenship behavior(OCB) through the experimental analysis regarding the mediating role of variables of trust. It also aimed to find out the effect that main subordinate variables of transformational leadership and empowerment leadership are influenced on the subordinate variables of organizational citizenship behavior. The result of study is summarized as followings. First, individual consideration of transformational leadership has a positive effect on the knowledge based trust.. It also impact of empowerment leadership has a positive effect on the knowledge based trust. On the other hand ,analysis show the knowledge based trust has a positive effect to altruism, civic virtue and sportsmanship of OCB. Second, individual consideration of transformational leadership has no effect to altruism, civic virtue and sportsmanship of OCB. The impact of empowerment leadership has a positive effect only on the civic virtue, other two hypothesis are not selected due to ineffective factors. The result, accordingly, of this study indicate that the knowledge based trust has a mediating role between leadership(transformational, empowerment leadership) and organizational citizenship behavior.