Abstract: The adsorption kinetics of C8 aromatic hydrocarbons in diethylbezene solution was studied by a transient method. The breakthrough curves of para-xylene, orthoxylene, ethylbenzene in diethylbenzene solution at 170℃ were measured respectively. From the breakthrough curves as well as the related parameters and relations, we analyzed and computed some properties. The controlling mechanism of the adsorption process for this system was also investigated and determined.