Barack Huseein Obama,the present president of America,was a constitutional teacher in University of Chicago Law School for more than ten years.Because of that,it has many aspects of significance to study about his views of constitution.Obama's discussion about constitution is centralized in the third chapter Our Constitution of his work The Audacity of Hope,which reflects his key idea of constitution—constitution is not only practical but also limited.Obama's views of constitution inspire us that do not to keep away from constitution,do not blindly believe in constitution,and do not demand too much on constitution.