At present，the geopolitical and Geo-economic competition in the bay of Bengal region is becoming increasingly fierce. In addition to China，three major powers - the United States，India and Japan - have different pattern of engagement in this region. The U.S. “arms” small regional countries with economic and security assistance，and nurtures India as a Geo-strategic chess player to share regional responsibilities；Under the principle of “Neighbor First” policy，India pursues a regional “spoke” strategy and strengthens the dominance of regional mechanism. Then Japan has used its economic advantages to seek strategic synergies with India，at the same time，Japan also strengthens economic and security support for countries in the region. The growing engagement of the U.S.，India and Japan in the bay of Bengal region is driven by a “strategic consensus” against China. On this basis，this paper finds that the Geo-strategic dynamic in the bay of Bengal presents three basic features：the trend of “strategic complementarity” among the United States，India and Japan in the bay of Bengal is strengthening；Regional small countries pursue “hedging strategy” among major powers；Competition differentiation between the traditional security area and non-traditional security area is obvious. In view of the adverse Geo-environment that China may face in this region in future，this paper finally attempts to provide a few brief Suggestions to promote China’s participation in the bay of Bengal region in future.