Confronted with the partisan polarization and divided government in his second term，President Obama has struggled with issues such as federal debt ceiling，government shutdown，NSA scandal，and Obamacare controversy. The political stalemate forced President Obama to take an inward turn in his political agenda. Under such context，the Obama administration is inclined to reduce its international commitments by withdrawing its troops in Afghanistan，reaching the Syria chemical weapons deal，negotiating an interim agreement with Iran over its nuclear program，reacting cautiously to the Ukraine situation. By doing so，the United States passed the responsibility and burden to the global and regional allies to maintain the U.S. international leadership image. This is called“multilateral retrenchment”strategy. With the guidance of this strategy，the Obama administration preferred diplomatic rather than military approaches in managing the international and regional issues. For the part of Sino-US relations，following the route mapped out by the“Sunnylands Summit”，the two countries achieved a lot extensive，and pragmatic high-level cooperation in political，economic，military and other issues. Meanwhile，Obama administration’s Asia-Pacific rebalancing strategy not only further complicated the security issues involving China，but also posed challenges for the two countries’ commitments in building a new type of major power relationship.