Abstract: An ultra performance liquid chromatography- tandem mass spectrometry( UPLC- MS / MS) method for determination of niacin in cereals has been developed. After spiking nicotinic acid- D4 as an internal standard,samples were extracted by sodium hydroxide and purified with solid phase extraction column. The mobile phase consisted of 10 mmol / L ammonium acetate with 0.1% formic acid and acetonitrile. The niacin was identified by multiple reaction monitoring( MRM). The results showed a good linear calibration in the range of 0.1 ~ 200 ng / m L( r > 0.999),the mean recoveries and the relative standard deviations were 99.3% ~ 102.6% and 4.24% ~ 4.74%,respectively.The limit of detection and quantification of niacin were 0.04 ng / m L and 0.1 ng / m L. This method is sensitive,time saving,and suitable for niacin determination in cereal samples.