,595 billion, ranking the 5th in the world, with dynamically developing member economies. Southeast Asia is expected to become a new momentum of growth, especially in the context that the global economy is on the brink of recession. Therefore, it can be said that the power that can control Southeast Asia will have a geostrategic advantage to strengthen its hegemonic ambitions in the 21s1 century.Through the lens of the Balance of Power theory, the article assesses Southeast Asia's position in the US and China's strategy, as well as how these two superpowers take use of Southeast Asia to gain advantages against competitors in such an area which will determine who takes the world no. 1 position in the 21stcentury.