The degradation kinetics of 2,4-dinitrophenol (2,4-DNP) and 2,6-dinitrophenol (2,6-DNP) were investigated in this paper. The degradation kinetics experiments were conducted in sequencing batch reactor (SBR) and the degradation model was analyzed by nonlinear regression to estimate parameters including the degradation rate Kmax, half saturation constant KS and the inhibition constant KI in the Andrews inhibition equation. The degradation inhibition in the condition of 2,4-DNP as solo substrate is more serious than that of the situation with glucose as co-substrate and Kmax decreases with the increase of inflow 2,4-DNP concentration. As for 2,6-DNP, Kmax gets maximum value is 0.019 mg/(mgSS×d) at the inflow concentration is 20mg/L. KS increases with the increasing of inflow 2,6-DNP concentration but there is no regularity for KI.