Abstract: A method for the pretreatment and qualitative detection of 26 trace cathinone new psychoactive substances in wastewater was established and applied in actual wastewater cases. The effluent samples were eluted on the Oasis PRiME HLB solid phase extraction column by ultra-pure water drenching and methanol solution, then dried with nitrogen at 40 ℃, and finally re-dissolved with 0.1% formic acid-acetonitrile solution (95∶5), and detected by liquid chromatography-tandem mass spectrometry, The effluent sample was determined by high-performance liquid chromatography-Tandem mass spectrometry (HPLC-MS/MS) using selected reaction monitoring (SRM) mode and separated on chromatographic column UPLC BEH C₁₈(100 mm×2.1 mm, 1.7 μm） at 35 ℃ with a mobile phase consisting of acetonitrile-0.1% formic acid in aqueous solution gradient elution. After methodological validation, the lower quantification of 26 cathinone new psychoactive substances could reach 1.50−3.00 ng/L. Among these, 21 analytes fell within the concentration range of 1.50−375.0 ng/L, while 5 were detected in the range of 3.00−750.0 ng/L, the correlation coefficient was 0.99, within-and between-batch precision was less than 7.71% and 13.91%, respectively, and the extraction recoveries were higher than 92.64% . The method is simple, accurate, and sensitive, and can be used for cathinone detection and abuse monitoring.