Abstract: Operating characteristics of acclimation processes of the aerobic activated sludge and the start-up period of the treatment of the butyl xanthogenate wastewater using membrane bioreactor (MBR) were discussed. The formation, morphology, character and mechanism for the pollutant removal of the aerobic active sludge using MBR were analyzed. Floccule sludge was acclimated using beer wastewater treatment aeration tank sludge as the inoculum sludge and with the sodium acetate and butyl xanthogenate as the carbon sources. The results showed that after 35 days start-up period and acclimated, the MBR system reached normal operating state with the SVI of the floc sludge of 100 mL/g and MLVSS/MLSS of 0.75, the removal rates of COD and xanthogenate of 80% and 90% respectively. The formation of floc sludge and membrane efficient rejection enhanced the stability of the MBR and provided a guarantee for the efficient degradation of the xanthogenate wastewater.