As the global energy landscape continues to reshape and strategic competition among major powers intensifies, energy security has become a crucial component of China’s and Japan’s foreign strategic layout. China and Japan are the two major energy consumers in Asia, so they have engaged in multi-level and multi-dimensional competition and interaction in Asia and Africa over energy resource acquisition, infrastructure construction, and the shaping of energy governance systems. Drawing on the perspectives of geopolitical economics and international energy politics, this article systematically examines the key approaches taken by China and Japan in oil and gas resource development, energy transport corridor control, power and new energy project investment, and energy technology exports across Asia and Africa. It also provides an in-depth comparison of strategic differences between the two countries in terms of policy instruments, corporate operating models, financial support mechanisms, and institutional norms. Through case studies of major countries in Southeast Asia, Central Asia, South Asia-Indian Ocean, and Africa, this article reveals that China-Japan energy competition has evolved from a single resource struggle to a comprehensive institutional competition. This article highlights that as the global trend towards green energy transformation intensifies, China and Japan will encounter new strategic opportunities and challenges in areas such as cooperation in third-party markets, the development of energy governance mechanisms, and the establishment of green standards in the future.