Objective To develop a method for determination of 18 sweeteners in high-fat cookies by ultra performance liquid chromatography-tandem mass spectrometry.Methods The sample was homogenized and extracted with methanol water （4∶1， v/v）， purified by solid-phase extraction， and separated on an Agilent ZORBAX Eclipse Plus C18 column （2.1×100 mm， 1.8-Micron）. The mobile phase gradient consisted of acetonitrile and 5 mmol/L ammonium formate aqueous solution. Quantification was performed using a liquid chromatography-tandem mass spectrometer with the external standard method.Results The 18 sweeteners exhibited good linearity within the concentration range of 5 to 1 000 ng/mL， with linear correlation coefficients exceeding 0.99. The detection limits were all 0.3 mg/kg， and the quantification limits were all 1.0 mg/kg. In spiked recovery tests at three different levels， the recovery rates ranged from 70.9% to 114.5%， with RSD values between 0.55% and 2.80%.Conclusion This method features a simple and rapid pretreatment process， high sensitivity， and reliable accuracy and precision， making it suitable for the determination of 18 sweeteners in high-fat cookies.