A method was developed for the quantitation of 3-nitropropionic acid in zymin by high performance liquid chromatography-tandem mass spectrometry(LC-MS/MS）.The analyte in samples was extracted with acetonitrile and the extract was purified with PSA solid phase extraction column.The separation of 3-nitropropionic acid was carried out on a Waters HSS T3 column by gradient elution using acetonitrile-water as mobile phase.The mass analyzer was performed in negative MRM mode.The result showed that the calibration curve of 3-nitropropionic acid was linear in the range of 12.5-125 μg/L with correlation coefficients more than 0993.The limit of quantitation(LOQ） was 5.0 μg/kg.The recoveries of 3-nitropropionic acid at different spiked levels ranged from 69.1% to 114.4% with relative standard deviations(RSDs） of 0.9%-8.9%.The real sample test showed that the method was simple，rapid and reliable.