The distribution and removal effectiveness of 6 PAHs (fluoranthene (FLT),benzo[b]fluoranthene (BbF),benzo[k]fluoranthene (BkF),benzo[a] pyrene (Bap),benzo[ghi]perylene (BghiP) and indeno[1,2,3-ed]pyrene (INPY)) in wastewater were monitored at different water treatment process in three Wastewater Treatment Plants by using Ultra performance liquid chromatography—tandem mass spectrometry (UPLC-MS/MS).For extracting PAHs from wastewater,the liquid-liquid extraction conditions were optimized and hexane was selected as extracting agent.The result indicated that (1) the total concentration of 6 PAHs were 427 ng/L,317 ng/L,and 219 ng/L in three wastewater treatment plant (WWTPs),respectively.For six PAHs,The content of fluoranthene in three WWTPs is the highest,which accounted for 62-66%.(2) For three different wastewater biological disposal process(the inverted A2/O process,oxidation ditch process,CASS process),the inverted A2/O process process got the best removal efficiency of 6 PAHs and the removal rate of PAHs was 93.3%.The PAHs removal rate were 90.7% and 80% by using the oxidation ditch process and CASS process,respectively.(3) For three wastewater treatment plant,different unit operations got different removal efficiency of PAHs.Biological treatment unit attained highest removal efficiency for PAHs,which was 72-86%.The next best is the Aerated grit chamber,and the removal efficiency for PAHs was 24-58%.