Abstract: To suppress the coke formation during utilization of hydrocarbon fuel is the key factor in practice. A set of chromatographic reactor system was set up for determining the coke deposition produced in the cracking process of endothermic hydrocarbon fuel. The chromatographic system was useful for study on coking mechanism through online analysis of products distribution. The system is suitable for studying coking inhibition over a wide range of conditions. Endothermic hydrocarbon fuel S-1 was selected as cracking feedstock. The effect of coking inhibitors carbon bisulfide and thiophene on the cracking of S-1 were studied, including coking rate, products distribution, weight loss of metal carrier, functions and properties of the coke. The functions and properties of coke formed on the metal carrier were characterized through SEM photographs. The results show that the coking rate of endothermic hydrocarbon fuel could be effectually restrained by sulfur-inhibitors. It is also found that carbon bisulfide is the better one that could decrease 90% of initial coking rate, while thiophene could decrease 40%. The distribution of paraffin and alkene in gas products was investigated on chromatographic system, and the alkene product distributions in cracking reactions is increased by carbon bisulfide and thiophene, which is beneficial for the improvement of endothermic property of fuel. Sulfur-inhibitor improves the configuration and hydrogen-carbon ratio of coke, which is in favor of coke-cleanup. Sulfur-inhibitor could also decrease the weight loss of metal carrier.