The objective of this paper is to investigate COD removal efficiency of the coking-plant wastewater by applying the moving-bed biofilm sequencing batch reactor (MBBSBR). The operation is simple and 30% WD-F10-4 BioM^(TM) were packed as carrier materials. It was found that the coking-plant wastewater could be effectively treated with 92.9% of COD removal efficiency at a low organic loading rate (OLR) of 0.449 kgCOD·m^(-3)·d^(-1). The removal efficiency decreased gradually down to 70.9% when OLR increased to 2.628 kgCOD·m^(-3)·d^(-1). The system has strong tolerance to organic shock loading in this experiment. The COD removal results in the blank experiments of biofilm and sludge showed that the attached biofilm has higher activity than suspended sludge and contributes about 60% to the COD removal.