Abstract: Objective To develop a method of quickly determining residual acrylamide in water treatment flocculant. Methods Samples were extracted by methanol and filtered through 0.2 μm membrane filters, then the content of acrylamide was analyzed by UPLC-MS/MS using ACQUITY UPLC^© HSS T₃ (1.8 μm, 2.1 mm×100 mm) column in a positive ion scan mode. The mobile phase was methanol and water. Acrylamide-d₃was used as an internal standard. Results The linear range was 0~1000 ng/mL and the correlation coefficient was 1.0000. The detection limit was 0.09 μg/g. The average recoveries were more than 98.5% and RSDs were less than 5%. Conclusions The method is simple, rapid, sensitive, accurate and applicable in the determination of residual acrylamide in water treatment flocculant.