In order to determine eleven commonly used veterinary antibiotics (including four tetracyclines, two sulfonamides, three quinolones and two macrolides) in piggery wastewater and activated sludge in the Yangtze River Delta region, the conditions of solid phase extraction and high performance liquid chromatography-tandem mass spectrometry were optimized. The recovery rate and relative standard deviations of the method were confirmed as 73% - 105.2%, 3.1% - 10.2% for piggery wastewater (n = 3) and 57.4% - 104.6%, 1.9% - 10.9% (n = 3) respectively for the activated sludge. Removal of antibiotics was then studied in a membrane bioreactor. The results showed that antibiotics of both tetracycline and sulfonamide species took a large portion in the wastewater, while tetracycline species were the dominant in the sludge. Tetracycline species in the wastewater were removed by 85.2%, mainly through biodegradation (51.9%) and secondly by sludge adsorption (33.2%). By comparison, sulfonamide species was removed by 95.8%, almost all through biodegradation while little by sludge adsorption. Flask tests suggested that the accumulated antibiotics in the sludge give no significant influence on the microbial removal of organics and ammonium.