Since entering the new century, the South Asian sub-continental attract more and more geopolitical attentions due to US's active global strategy, especially the "Pivot to Asia" policy in Obama period. Furthermore, US tried to draw India over to her side because China's launched the so-called Belt and Road Initiatives (BRI) since 2013-14. In this paper, we'll focus on the sensitive geopolitical framework among US, China and India around South Asia, and try to analyze their possible interactions through the strategic triangle approach.