Abstract: A study on the composition of hydrocarbons as well as their distributions of classification and carbon numbers in rocket kerosene was made by the application of GC and FI-TOF-HRMS in hyphenation. Sample of rocket kerosene was introduced directly into the instrument for analysis. It was shown by the analytical results that: ① the carbon number of the hydrocarbons present in the kerosene sample was in the range of C8-C16; ② content (w/%) of alkanes amounted to 19.9%; total cyclic hydrocarbons amounted to 77.7% (induding 42.9% of monocyclic hydrocarbons and 33.4% of bicyclic hydrocarbons; amount of arenes (all as monocylic arenes) attained only to 2.4%; ③ no S-, N- and O- containing heterocyclic compounds present as impurity were found in the kerosene. The above results were found to check very well with the results obtained by GC-MS.