Abstract: Residual amounts of DON, 3-Ac-DON and 15-Ac-DON in cereal grains and its products were determined by HPLC-MS/MS. The sample was extracted by a mixture of acetonitrile and water, and the extract was defatted by hexane and purified on HLB SPE column and then the solution was analysed by HPLC-MS/MS. External standard method was adopted for quantification. Linear relationships between values of peak area and mass concentration of the 3 DONs were kept in the same range of 10.0-500 μg·L-1, with values of detection limits (3S/N) for the 3 DONs of 4 μg·kg-1, 0.5 μg·kg-1 and 3 μg·kg-1 respectively. Values of recovery obtained by standard addition method were in the range of 79.7%-103%, with RSDs (n=6) in the range of 8.8%-19%.