Although the international financial crisis weakened the position of the United States，because of its global military share of 43 percent，the United States remains an influential military power. During the 2009-10 period，U.S. military strategy made some adjustments. On the one hand，with the withdrawal of troops from Iraq，military strategy turned to Afghanistan. On the other hand，the U.S. emphasized diplomacy and called upon its allies to share responsibility. The process of the U.S. strategic eastward movement in military deployment and diplomacy is a consequence of China’s rise. In the area of arms control，the United States and Russia signed a new nuclear disarmament treaty，but there are still conflicts over the anti-missile issue. The first nuclear safety summit expressed the common wish of the participating countries to maintain and enhance the system of international nuclear non-proliferation. However，there is still a long way to go to ultimately eliminate the threat of nuclear weapons.