The heat sink is one of the key indicators of the development of endothermic hydrocarbon fuels, and the total heat sink of endothermic hydrocarbon fuels can be increased by enhancing the chemical heat absorption capacity to meet the cooling requirements for future high-performance aircraft. The supercritical pyrolysis and endothermicity capacity of n-decane (a major component in endothermic hydrocarbon fuels) are studied under different pressures. Experimental results indicate the main gas products are small molecular hydrocarbons (methane, ethane, ethylene, etc.), ethylene and propylene are the most abundant components at current experimental conditions. It is noticed that the influence of pressure on the production of ethylene is greater than that of any others. The increase in pressure increases the conversion of fuel to enhance its endothermicity, but the increase in pressure also decreases the alkene/alkane ratio, which has negative effect on the improvement of the chemical heat sink of fuel. So the influence of pressure on the endothermicity of n-decane is not a simple effect of promotion or inhibition, the regularity is different in different temperature ranges. (C) 2014 Elsevier B.V. All rights reserved.