In the year 2019 there were continuing changes in the relations among the major powers. The Sino-Russian relationship began an even higher level of cooperation，Sino-U.S. relations entered a “new normal” state in which competition and cooperation coexisted in various fields. The nebulous “New Cold War” still clouded U.S.-Russian relations. Other major countries adjusted their diplomatic strategies accordingly. Among all bilateral relationships，there was both consensus and disagreement，and the possibility of conflict and confrontation continued to exist. As the world was undergoing profound changes that did not exist in the former century，relations among the great powers faced new challenges，calling for both theoretical improvements and policy adjustments.