Entrepreneurship as any Emergence scientific field is confronting with scientific legitimacy. Entrepreneurship as a scientific field has received increasing attention but doesn't acceptance as well as. From this point of view entrepreneurship is confronting with legitimacy challenge. In this article Entrepreneurship as a emergence scientific field that is based on the five dimension consist of: subject, strong conceptual model, distinctive methodology, the research, training and publication situation and professional implications, is discussed. The findings of this article have indicated that entrepreneurship is confronting with legitimacy challenge. To get ahead of this challenge should more pay attention to dimensions of ground conceptual model, research methodology, explorative and theoretical researches.