In the early 21st century, China has increasingly recognized the critical importance of securing its national energy supply. As the demand for energy continues to rise, China has implemented an assertive and comprehensive energy diplomacy strategy on a global scale, with Southeast Asia emerging as a key focus. The region holds a geo-strategic significance, rich in vital natural resources such as oil, natural gas, and other minerals, making it a strategic partner in China’s broader energy security objectives. This policy, driven by China’s growing energy needs and its desire to diversify energy sources, has far-reaching impacts on Southeast Asia, influencing various sectors including economics, politics, and national security. China's energy diplomacy in Southeast Asia is not only an economic endeavor but also a means of strengthening political alliances and asserting its regional influence. This paper explores the nuances of China's energy diplomacy policy towards Southeast Asia in the early 21st century, highlighting its strategic objectives, the mechanisms employed, and the broader implications for regional and global security dynamics.