A　method　for　simultaneous　detection　of　28　mycotoxins　in　wheat　flour　was　established　by　ultra　performance　liquid　chromatography-tandem　mass　spectrometry.　Samples　were　extracted　with　acetonitrile/water/formic　acid　(80:　18:　2),　separated　by　C18　column,　monitored　using　multiple　reaction　monitoring　(MRM)　mode,　and　quantified　with　the　external　standard　method.　The　results　of　methodological　verification　under　high,　medium　and　low　addition-concentration　levels　showed　that　the　recoveries　of　the　three-level　spiked　samples　ranged　from　60%　to　120%,　and　the　relative　standard　deviations　were　less　than　11%,　which　could　meet　the　laboratory　quality　control　specifications　required　in　the　national　standard　GB/T　27404-2008.　Using　this　method,　the　samples　of　wheat　flour　on　the　market　were　tested,　and　the　results　showed　that　deoxynivalenol　and　its　derivatives　and　fumonisin　were　the　major　contaminants.　In　some　samples　the　content　of　deoxynivalenol　exceeded　the　national　limit　(＜1　000　μg/kg).　The　method　could　be　used　for　the　simultaneous　sample　pre-process　and　detection　of　28　mycotoxins　in　the　wheat　flour　matrix　and　could　be　applied　in　the　daily　risk　monitoring.　©　2020,　Dept.　of　JCCOA.　All　right　reserved.