In October 2021 and October 2022，Fumio Kishida and Rishi Sunak became Prime ministers of their countries respectively，marking the Sunak-Kishida era of UK-Japan relations. The Sunak government and the Kishida government faced common international challenges，pushing them to seek support from each other. At the same time，the United States also helped to promote the strategic coordination between Britain and Japan，the two most important allies on the side of the Atlantic Ocean and the Pacific Ocean respectively. Therefore，the pace of building a “global strategic partnership” between Britain and Japan has accelerated significantly. With the signing of the Hiroshima Accord between the UK and Japan in May 2023，the two countries have deepened substantive cooperation in the fields of politics，security，economy and trade，investment，science and technology，and infrastructure. The strengthening of UK-Japan strategic coordination not only impacts the security environment，economic and trade architecture，and the strategic pattern of global powers in the Indo-Pacific region，but also indirectly affects the bilateral relations between China and the UK，China and Japan，as well as China’s surrounding security environment and national interests. Therefore，China also needs to pay close attention to the trend and impact of the strategic cooperation between Britain and Japan.