A high performance liquid chromatography-tandem mass spectrometric（HPLC-MS/MS)method was developed for the determination of 8 kinds of mycotoxins（aflatoxin B1，aflatoxin B2,aflatoxin G1,aflatoxin G2，fumonisin B1，fumonisin B2，sterigmatocystin and roquefortine C) in cereal.The sample was diluted with hexane to remove the oil,then extracted with 60% acetonitrile.The acetonitrile layer was made up to constant volume and passed through the filter before tested.The detection was performed in the electrospray ion positive mode and multiple reaction monitoring（MRM) mode，and the quantitation of target compounds was carried out by the isotope dilution assays.The results indicated that the 8 compounds showed good linear relationships in certain concentration ranges,with correlation coefficients not less than than 0.997 0.The average recoveries ranged from 77% to 123%,with relative standard deviations of 0.6%-13.3%.The method was proved to be rapid and sensitive,and could be used for the detection of mycotoxins in cereal.