The South China Sea dispute is a complex territorial and maritime dispute that involves the territorial claims of several countries, including China, Vietnam, the Philippines, Malaysia, Brunei, and Taiwan. China claims absolute ownership of a large area of ​​the waters in this region, which has caused disputes with coastal countries and the United States. Beijing's increasing assertiveness in the South China Sea territorial dispute and the expansion of air and naval patrols in the region are considered a strategic threat to coastal countries and the United States, which has led to Washington's regional presence and the creation of alliances with coastal countries to contain and control Beijing in East Asia. Thus, the main question of the research is what measures has the United States taken in response to China's increasing assertiveness in the South China Sea dispute? The research hypothesis is that China's increasing military-defense power and its efforts to convert artificial reefs and islands in the South China Sea into military bases have increased Beijing's disputes with coastal countries and the United States. In response to Beijing's growing threats in the South China Sea, the United States has increased its presence and influence in this strategic waterway and is trying to prevent Beijing's growing power in the region by establishing alliances with its regional allies and holding naval exercises, which will increase tensions and create a security dilemma in the Asia-Pacific region. A descriptive-analytical method was used to analyze the research data.