A reliable，sensitive and selective method was developed for the determination of 4 macrolide antibiotics（MLs） in typical waste water and activated sludge using high performance liquid chromatography-electrospray ionization tandem mass spectrometry（HPLC-ESI-MS/MS）.The target antibiotics in water samples were enriched and cleaned up with HLB solid phase extraction cartridges，and then eluted with 6 mL methanol.The activated sludge sample was ultrasonically extracted with a mixture of acetonitrile-phosphate buffer.The eluate was collected and concentrated under a gentle stream of nitrogen gas.The target compounds were separated on a Waters Symmetry-C18 column with acetonitrile-10 mmol?L-1 ammonium acetate as mobile phase，and analyzed by HPLC-ESI-MS/MS under positive electrospray ionization and selected reaction monitoring mode.Good linearities of 4 MLs were achieved over the concentration range of 0.1-100 μg?L-1，with correlation coefficients above 0.99.The overall recoveries of 4 MLs in waste water and activated sludge matrices were in the ranges of 70.2% -90.6% and 75.6% -88.7%，respectively，with relative standard deviations（RSD，n=6） of 2.7%-7.8 %.The method detection limits of 4 MLs in water samples and activated sludge were in the ranges of 0.013-0.025 ng?L-1 and 0.09-0.22 ng?g-1，respectively.The developed method was applied in the analysis of the typical waste water and activated sludge in Shihezi，Xinjiang,and the results indicated that the target antibiotics were detected in all samples.