Abstract: The conversions of tetramethylbenzene and diethylbenzene, the main components in C10 fraction, to light aromatics on nano-ZSM-5 were studied in a pulse micro-reactor. The results show that at low temperature, isomerization of tetramethylbenzene is the main reaction, while at high temperature, the reaction is changed to dealkylation and transalkylation. The space velocity affects the competition of the two kinds of reactions of tetramethylbenzene. As to diethylbenzene, the dealkylation is the main reaction. If the maximum amount of BTX is the reaction goal, low space velocity and low temperature are the optimum reaction conditions for both of the reactants. The optimum reaction conditions can be used for lightening the C10 aromatics fraction in industrial unit.