Work engagement is a widely concerned issue in recently years. In the past for a long time, we pay more attention to the negative side of the employee in the workshop, for example “job burnout” and “emotional exhausted” etc. With the emerging of the positive psychology, the positive side about the human arouses the interest of the researchers gradually. In the meanwhile, academic community pays more and more attention to the work engagement instead of job burnout in the past. Compared with the traditional focus on the negative side and trying to correct the bad behaviors, work engagement pays more attention to the positive side of the human nature and trys to develop these positive qualities .So, factors that can improve the work engagement have been the hot focus in the academic area. Recently, many scholars have made lot of deep researches about how to improve the employee’s work engagement. However, it is pity that there are few studies about the influence of the employees' work engagement from the aspects of leadership behavior. As a new leadership style based on the ethic element rather than talent element, authentic leadership seemly was more correspond with the Chinese traditional culture. In the Chinese traditional culture, we values ethics more than talent. Therefore, researches about the relationship between authentic leadership and work engagement make more sense in Chinese culture background. The study focuses on the authentic leadership and deeply researches into the internal mechanism that authentic leadership affect the work engagement. By the method of structural equation model with Mplus7, the study checks the mediation role of the professional identity, affective commitment and perceived organizational support between the authentic leadership and the employee’s work engagement. The result with Mplus7 shows that: (1)the professional identity plays a partial mediation between the authentic leadership and the work engagement (indirect effect β=0.256, p<0.001);(2) affective commitment plays a partial mediation between the authentic leadership and the work engagement (indirect effect β=0.247, p<0.001);(3) perceived organizational support also plays a partial mediation between the authentic leadership and the work engagement (indirect effect β=0.079, p<0.05);(4)the total indirect was also significant (β=0.582, p<0.001).When considered all the mediation variables in the meanwhile, professional identity, affective commitment and the perceived organizational support play a completely mediation effect between the authentic leadership and the work engagement, that is, the effect of authentic leadership to the work engagement is completely through the professional identity, affective commitment and the perceived organizational support. Based on the result, we can come to a conclusion that: as a leadership style focused on the ethics, authentic leadership can positive influence on the employees' work engagement through the professional identity, affective commitment and the perceived organizational support. A leader can improve the employee’s work engagement trough his or her authentic leadership. The present study contributes to the current literature and promotes our understanding about the relationships between the authentic leadership and the work engagement.