@@@@The increase of global competition, consolidation, and innovation brought up pressures and urged the emergence of work teams as basic building blocks of organizations. As consequence, more and more organizations shifted from work organized around individual-base job to team-based work structures. Recent organizational researches confirmed that work team members’ organizational citizenship behavior had unique meaning to facilitate the effective functioning of work team. @@@@The purpose of this article was to explore how work team leaders’ psychological capital influenced on their direct followers’ organizational citizenship behavior. Sixty-six work teams (66 work team leaders and their 303 followers) were sampled from a large State-owned enterprise in eastern China. Data were collected from leaders and their direct followers respectively. Both work team leaders and their followers self-rated their own level of psychological capital. Besides, work team members also finished an organizational citizenship behavior self-report questionnaire. @@@@Structural equation model (SEM) and hierarchical linear mode (HLM) were applied to analyze the survey data. After controlling demographic and human capital variables, such as, gender, age, marriage, educational level and organizational tenure, hierarchical linear modeling results revealed that work team leaders’ psychological capital was positively related to their direct followers’ organizational citizenship behavior, work team members’ psychological capital was a cross-level mediator between work team leaders’ psychological capital and their followers’ organizational citizenship behavior. However, this research didn’t support the hypothesis that the relationship between work team members’ psychological capital and organizational citizenship behavior was moderated by work team leaders’ psychological capital such that the relationship was stronger when work team leaders’ psychological capital was perceived to be high versus low. This finding was different from that of western organizational background. @@@@Our findings revealed that both work team leaders and members’ psychological capital were positively associated with work team members’ organizational citizenship behavior. The result suggested that psychological capital, especially work team leaders’ psychological capital, was a key element for constructing efficient work teams. Entrepreneurs could do everything possible to improve work team leaders and members’ psychological capital to enhance work team efficiency and organizational performance.