<p>Carbon/epoxy sandwich laminate (CESL) have been extensively employed in civil aircraft load-bearing structures. Nevertheless, the inherent flammability of their epoxy resin matrix poses critical aviation safety challenges, particularly given that most fire-related fatalities in confined spaces stem from smoke-induced disorientation. To systematically evaluate these risks, a comprehensive experimental investigation and theoretical analysis were conducted to characterize the thermal decomposition, fire reaction properties, and smoke characteristics of CESL. The thermal decomposition, heat release, and mass loss processes were analyzed, with typical pyrolysis kinetic and smoke dynamic parameters calculated. Additionally, the effect of combustion conditions (flaming versus smoldering) on smoke characteristics was explored. It was determined that the thermal decomposition and combustion reactions of CESL consist of four steps and three phases, respectively. More importantly, both forming process and combustion condition has a significantly effect on smoke production and density properties. These experimental data, combined with theoretical analysis, offer insight for investigating fire accidents and provide useful guidance for enhancing the reliability of structural composites and the effectiveness of fire protection systems in aircraft.</p>