<p>This study discusses the influence of energy security on carbon dioxide (CO₂), using China’s 30 provincial data and panel fixed-effect model. The empirical results identify the potential mechanism of impact and draw several important conclusions. First, energy security can reduce CO₂ emissions, which means that China’s energy security strategy does not contradict its carbon targets. Second, energy security reduces CO₂ emissions through optimization of energy structure and enhancement of energy efficiency. Third, energy security in southern regions and provinces with light environmental regulations significantly inhibits CO₂ emissions. The results of this study go beyond simple causation and reveal specific mechanisms through which energy security affects CO₂ emissions. This work provides a thorough analytical framework and practical policies for addressing energy and environmental challenges. Thus, China ought to advance the exploitation of renewable energy sources, diversifying energy utilization structure, and enhance the national total energy system efficiency.</p>