To develop a rapid method for determination of zearalenone in grain and its products by liquid chromatography tandem mass spectrometry (LC-MS/MS) and provide analytical methodology for the wheat flour and corn flour in Ningxia.Methods Samples of grain and its products were ultrasonically extracted by acetonitrile-water (84∶16) solution and cleaned up by PriboFast 226 multifunctional clean-up column. Zearalenone was separated on Atlantis T₃ chromatographic column with mobile phase of methanol-10 mmol/L ammonium acetate on gradient elution. The zearalenone was determined and quantified by mass spectrometry. Results The average recoveries of zearalenone in wheat and corn samples at three spiked levels were 85.4%-93.7% with relative standard deviations less than 9.0%. The limit of detection (LOD) and the limit of quantitation (LOQ) were 0.08 and 0.2 μg/kg respectively.Conclusion The method was accurate, reliable, and could be used as a quality control method for zearalenone in grain and its products.