The main purpose of the study is to discuss the influence of transformational,transactional leadership on leadership effectiveness and the mediating effects of leader-member exchange. By a survey of staffs of enterprises and institutions in southern China’s Xiamen,Foshan,Changsha,and Hefei city,the study empirically explores the relationship among transformational and transactional leadership,leader-member exchange and leadership effectiveness separately from high order construct level and dimensions level of leadership behavior. The results show that: (1) Overall,transformational and transactional leadership have significant positive impact on leadership effectiveness. However,different dimensions of leadership behavior have different impact on leadership effectiveness variables. (2) Overall,leader member exchange has partially mediating effect in the two pairs of relationships between transformational leadership and leadership effectiveness,and transactional leadership and leadership effectiveness. But not all leadership behavior dimensions have impacts on leadership effectiveness through leader-member exchange. The conclusions provide some guiding thoughts for transformational and transactional leadership practice under the background of China.