The combustion of pyrolysis products of endothermic hydrocarbon fuel was studied experimentally to demonstrate the variation in the combustion characteristics after regenerative cooling. The experimental results show that the pyrolysis liquid produced from different cracking conditions have similar combustion characteristics to the original fuel. The different pyrolysis gases show very similar combustion characteristics even under very different conversion rates. Therefore, no remarkable differences in the combustion characteristics were found in the practical pyrolysis products (mixtures of pyrolysis liquid and pyrolysis gas), and the differences between their combustion characteristics remain essentially the same with changes in the cracking pressure and mass flow rate once the inlet and outlet temperature are settled. An analysis also shows that the liquid phase of the pyrolysis product has a greater effect on the combustion characteristics of practical pyrolysis products than the gaseous phase, but the discrepancy between their relative effects is insensitive to the combustion pressure.