Objective: This study aimed to establish a rapid screening and confirmation method for the 45 kinds of antibiotics, including quinolones, sulfonamides, nitroimidazoles and macrolides in aquatic vegetable, by ultra-high performance liquid chromatography-triple quadrupole-linear ion trap mass spectrometry (UPLC-Q-Trap-MS). Methods: The sample was extracted with acetonitrile containing 0.1% formic acid, then cleaned up with primary secondary amine (PSA), anhydrous magnesium sulfate (Na₂SO₄) and C₁₈. The analytes were detected by UPLC-Q-Trap-MS in the multiple-reaction monitoring with information-dependent acquisition of enhanced product ion (SMRM-IDA-EPI) mode, followed by matching retrieval of a multiple antibiotic database. The 45 kinds of antibiotics were confirmed by retention times and ion pairs through database searching using the EPI library and quantified by external standard method. Results: All the antibiotics showed good linearity with correlation coefficients above 0.99 when the concentration falls in the range 1.0~100.0 μg/L. The limits of detection (LOD) were in the range of 0.3~1.0 μg/kg, and the limits of quantitation (LOQ) were in the range of 1.0~3.0 μg/kg. The average recoveries for 45 antibiotics at three spiked levels ranged from 60.4% to 121.7%, with relative standard deviations (RSD) of 0.9%~10.2%. Conclusion: The method is rapid, simple and qualitative, and is suitable for the screening, confirmation and quantitative detection of the 45 kinds of antibiotics residues in aquatic vegetable.