Abstract:

US-Japan relation is one of the most important bilateral relations in the world，and third-party factors pose certain impact on the stability of the alliance. Both countries have been seeking a strategic position in Asia-Pacific region，where the situation has been changing with the rise of China and Russia. US and Japan may strengthen their cooperation or separate from each other or contend with each other due to the third-party factors with China strengthening or separating the US-Japan alliance，and Russia checking or weakening US-Japan relations. In the future，US-Japan relation is characteristic of strengthening alliance，and the third-party factor will also co-exist with US-Japan alliance. China，as a major third-party，has faced with opportunities and challenges after the“One Belt，One Road”initiative. In the US-Japan relations，China needs to implement diplomatic policies which are able to better safeguard national interests，and to further develop China’s all-round diplomacy.

Key words: US-Japan relation, Asia-Pacific region, the third-party factor, China, Russia