During the 2009 to 2010 period，there has been a general structural change in the relationship among the major powers.On the one hand，because the U.S. became more deeply entrapped in the Iraq war，the Afghan war，and the financial crisis，its ability to control global events was weakened；on the other hand，the G20 became the main forum for the world economy，indicating that the status and influence of the emerging powers had increased significantly. Due to this trend whereby one is falling and another is rising，China’s position has been highlighted and the ups and downs in Sino-American relations have become the most important pair of relations among the major powers.Because the interactions between China and the U.S. have been restricted by a dual structure，which includes both power competition and interdependence，although the conflicts on both sides have sharpened during the past year and interactive swings have increased significantly，the conflicts remain under control. In the process of the structural changes among the major powers，other rising powers are emerging to play a growing role. These new trends constitute an important phenomenon in global political multi-polarization.