Against the backdrop of global energy structure transformation and deepening climate governance, the scale of China's energy investment in "Belt and Road" countries is continuously expanded and its structure is increasingly diversified. Given that the environmental impact of energy investment projects was characterized by long-term persistence, based on the data of fifty-four countries from 2008 to 2024, a fixed effect model and quantile regression method were built to explore the relationship between China's foreign energy investment and the green development of host countries. The results show that the countries' green development level is significantly promoted by China's energy investment, and the green promotion effect is stronger in countries with lower GTFP levels. A series of robustness and endogeneity tests was conducted. Meanwhile, the promotion of green development in countries by China's energy investment was achieved through four channels: investment structure optimization, green financial support, green technology innovation, and digital infrastructure construction. Furthermore, heterogeneity was demonstrated in sub-samples when investment form, investment location, and host country characteristics were considered. The green development effect of China's foreign investment in clean energy and greenfield merger and acquistion was found to be stronger, and the green development level of land "Silk Road" countries, Asian countries, middle-income and low-income countries, and countries with a low institutional environment was significantly enhanced. A theoretical basis and empirical support are provided by the results for actively responding to international public opinions and doubts, such as the "China pollution shift theory" and the "China environmental threat theory", and for continuously promoting the green "Belt and Road".

foreign energy investment  /  "Belt and Road" initiative  /  green development level  /  optimization of investment structure  /  green financial support  /  green technology innovation  /  digital infrastructure construction