This article evaluates the possibility of ‘Thucydides’s Trap’ between the U.S. and China through defensive realism. The possibility of U.S.-China conflict has been mainly discussed in the frame of offensive realism. It argues that if China’s rise continues, it will cause serious military conflict between the two. However, it is unclear whether the crisis will turn into an actual conflict. Defensive realism provides an alternative perspective. However, the interpretation by defensive realism in contrast to offensive realism has not been highlighted. Considering the importance of defensive realism, there is a theoretical gap for the most important global issue. Most realist explanations predict U.S.-China relations as serious conflicts, but defensive realism posits that it does not necessarily have to be pessimistic. This article draws the concepts of a state’s motivation and type, status quo, security dilemma, and grand bargain, reinterprets U.S.-China relations, and presents alternative policies.