It isn't good for America to expand its hegemony at the beginning of the new century.America's ability to control its traditional allies is inevitably on the decline.America's army garrisoning Central Asia and South Asia has increased its hegemonic cost, and may also bring about some gravediggers to its hegemony. The unprecedented expansion of America's hegemony will be bound to evoke international community's universal dislike,so it's difficult to continue its hegemony.