The biodegradation of mixed cultures was analyzed. The paper studied the effects of treat condition (static and shaking), concentration of dye, activities of oxidative enzymes (LiP, laccase and Manganese Peroxidase) and the bioaugmentation effects of the activated sludge system. The results showed that mixed cultures were able to degrade Reactive Brilliant Red X-3B and Direct Blue-6 (100 mg/L) completely within 32 h in shaking condition. As the initial concentration of Reactive Brilliant Red X-3B increased from 100mg/L to 900mg/L, the decolorization rate still maintain a high level only decreased from 99.3% to 83.5%. Induction in the activity of oxidative enzymes (LiP, laccase and Manganese Peroxidase) represented their role in degradation. In augmented experiments, it showed that in the control SBR system with the CODCr of the effluent was in three average levels 848, 1228, and 1550 mg/L, the CODCr degradation rates were 42.3%, 32.8% and 19.7%. In the augmented system treated with the same effluent, the degradation rates of augmented system were 86.5%, 71.8% and 59.8% respectively. It showed that the activated sludge was augmented by the mixed cultures which made the system to be more stable and improve impact resistance.