Abstract: Polymeric substances（EPS）in brewery surplus activated sludge were extracted and compared with four different methods of NaOH，heating，streaming and iron-exchange. The EPS obtained was used for sludge flocculation and conditioning. The EPS extracted with NaOH method showed 45.4% flocculation rate. The EPS was beneficial for sludge settling and filtering，because of that the specific resistance of sludge could be declined by 15.2% with the EPS extracted with NaOH method.