Transformational leadership positively influences employees' organizational citizenship (OCB) and reduces their intention to leave the organization. It is of theoretical and practical importance to further clarification what mechanisms and processes explain the positive impact of transformational leadership. The objective of this research is to explore if supervisor-subordinate communication mediates the relationship between transformational leadership and intention to leave (ITL)/OCB. The sample consisted of 1962 employees from state-owned companies in China. The results of Exploratory Factor Analysis and the Confirmatory Factor Analysis showed that measurements of communication, leadership and OCB had high reliability and validity. The results showed that transformational leadership was positively related with supervisor-subordinate communication, OCB, and negatively related with ITL. Further regression analyses supported the assumption that supervisor-subordinate communication mediated both the leadership-ITL and leadership-OCB relationship. The SEM results showed that supervisor-subordinate communication mediated only leadership-OCB relationship. The results are discussed in the light processes that explain the influence of transformational leadership. With regard to practical implications propositions are provided that help to enhance the quality of the communication between supervisors and subordinates.