U.S.-Pak relation is the typical example of the interactions between the global conflict and the regional conflict. The United States value Pakistan most is the contribution to the containment communism and counter terrorism. And Pakistan’s ultimate demand in the U.S. is to enhance the ability to resist India. The United States is much stronger and richer than Pakistan. The national interests of the two countries are often conflicting. All these result in the U.S.-Pak relation has many characteristics. The study of these characteristics is very helpful to understand the relationship between the two countries