In recent years, since the Obama Administration, the policy discussions on the Indo-Pacific region have gradually moved from conceptualization to strategy. The Indo-Pacific strategy is established during the Trump Administration, in which, Japan played a leading role. The Indo-Pacific strategy is advanced jointly by the United States and Japan. In this process, the three characteristics of dual ambiguity, dual assurance and dual check are taking shape, which has a compound influence on the Japan-U.S. alliance and showed the interaction between tension and synergy. Compared with the Asia-Pacific strategy, building a huge Indo-Pacific strategy requires more costs, and Indo-Pacific countries are paying close attention to its development trend.