A solid- phase extraction (SPE) followed by liquid chromatography - electrospray ionization - tandem mass spoc-trometry (LC -ESI- MS/MS) method was developed and validated for simultaneous analysis of 22 various target antibiotics,including sulfonamides,trimethoprim,tetracyclines,macrolides and fluoroquinolones.Compounds in the water samples were enriched through Oasis HLB cartridges and detected in multiple reaction monitoring (MRM) mode.SPE and instrumental parameters were optimized.The recoveries for the investigated antibiotics ranged from 60％ to 105％ for spiked tap water,60％ to 94％for urban surface water and 60％ to 95％ for municipal wastewater,respectively.The limits of quantification (LOQ) was defined as a signal - to - noise ratio of 10 and the LOQs of target compounds were between 1.2 and 10.6 ng/L.This method was applied to the survey of antibiotics in the Yuqiao Reservoir and ambient waters,the major drinking water source of Tianjin,China.Monitoring data demonstrated that the western part of Yuqiao Reservoir was polluted by sulfathiazole and sulfacetamide.Moreover,fifteen target antibiotics including sulfonamides,trimethoprim,and four fluoroquinolones were detected in the ambient water samples.The tetracyclines and macrolides were not detected in the Yuqiao Reservoir and ambient waters.Although the concentrations of antibiotics in Yuqiao Reservoir and ambientwaters were at relatively low levels,the risks of their potential harms to aquatic organisms and human health should be noticed.