The idea of renegotiating the North American Free Trade Agreement( NAFTA) w as put forw ard by the current US government during the election campaign and has become a reality after taking office. The existing research mainly interprets the renegotiation from the perspectives of election,interest groups,game betw een big pow ers,and trade imbalance,etc. How ever,such a renegotiation arrangement hardly has economic rationality and obtains broad domestic support if the foundation of integration has not been sh...