In the 2010s, China’s memory of World War II played an essential role in promoting nationalism domestically and constructing China’s international identity in the global society. As China’s ally during World War II, the United States has become the primary focus of Chinese war memory in recent decades. Overall, the Chinese government gave a positive and fair representation of the Americans joining the War of Resistance in the official memorialization. In this essay, I argue that by portraying the Sino-American alliance in World War II as an amiable and sublime partnership between the two states, the Chinese authorities strived to construct the just and international images of wartime China to facilitate cosmopolitan China in the global society, as well as use the collective war memory as the adhesive of the volatile Sino-American relations in the 2010s. The sources are from the fieldwork I conducted in January 2022 in the state-owned war museums in southwestern China, where the wartime military cooperation happened. I explore how the Chinese government in the 2010s represented the wartime alliance and the United States by manipulating the exhibits, wall texts, images, and sculptures in war museums; which aspects of the history the authorities chose to omit; and why the Chinese authorities constructed the cosmopolitan-oriented war memory.