Compared to other administrations after the Cold War，the Obama administration made significant changes to its Asia-Pacific policy. Multiple factors urged Obama administration to “rebalance” U.S. government attention and resources toward the Asia-Pacific region. The Obama administration has actively implemented the following strategies：strengthen and refurbish traditional alliances；actively forge new partnerships with emerging powers from Asian-Pacific region；and increase its interaction with the ASEAN under the multilateral framework. The “Rebalance” strategy has three main features. First，the “Rebalance” of military affairs will make progress much faster than other aspects of the policy；its planning is much more thorough. Second，the Trans-Pacific Partnership （TPP） will become a major pillar in President Obama’s rebalance in terms of economic statecraft. Third，the “Rebalance” will also be carried out within the Asia-Pacific region. In other words，priority is shifted from Northeast Asia to Southeast Asia. Although the U.S. government is positive about the “Rebalance” strategy and makes great efforts to implement it，many challenges remain. First，the “Rebalance” policy arouses suspicion from China. This creates obstacles to cooperation with China regarding important global issues. Second，slow progress in non-military fields causes observers to view the “Rebalance” as a policy limited to national defense. Third，a deep cut in the defense budget leads to a reduction of its military forces. Finally，turmoil in the Middle East and the Ukraine crisis distracts the U.S. from matters in the Asia-Pacific region. The Obama administration then becomes subject to criticism due to its weakness in fulfilling its commitment. If the U.S. cannot effectively address these new challenges，the implementation of the rebalancing policy will be seriously affected.