As communist countries in East Asia, China and Vietnam have made remarkable economic achievements since their economic opening. Since 2018, the trade war between the United States and China has had an important impact on the economic development of the two countries, including the Changes in Sino-Vietnamese economic relations. This paper will use literature analysis and international political economics theory to analyze the impact of the Sino-Vietnamese economic development before and after the impact of the U.S.-China trade war. Under trade restrictions, Chinese companies turned to the Vietnamese market, which promoted the increase in Sino-Vietnamese trade, but China's economic growth slowed down. The slowdown has had a negative impact on Vietnam's exports. Therefore, an in-depth study of the economic development of China and Vietnam under the US-China trade war and the changes in China-Vietnam economic relations will help to better understand the economic situation and trends in East Asia, and provide policy recommendations to deal with possible challenges.