A fluidized-bed bioreactor was used to treat the industrial wastewater containing linear alkylbenzene sulfonate(LAS). Microorganism obtained by acclimation showed low growth rate and substrate inhibition at relatively high substrate concentration. It was found from the experiment using fluidized-bed bioreactor that 64㎛-thick biofilm was made after 15 days. The 93.4% LAS removal efficiency in the reactor was obtained at 120㎎/L of intial LAS concentration. while the removal efficiency of sulfophenylalkanoates(SPA) which is a representative intermediate of biodegradation of LAS was 60-80% depending on the initial concentration of LAS. When sodium benzoate was added to the second reactor, the remaining SPA become lowered by 40% compared to the control experiment. And when activated carbon was added to the reactor, the removal efficiency of SPA was 96.2% and that of LAS was 100% when initial inflowing concentration of LAS was 350㎎/L.