An analytical method was developed for the identification and detection of semicarbazide(SEM) residues in flour and flour products by high performance liquid chromatography coupled to quadrupole/linear ion trap mass spectrometry(HPLC-QTRAP/MS).Samples were reacted with o-nitrobenzaldehyde in HCl with assistant of ultrasonic to produce stable derivative,and then the derivative was cleaned up with PLS SPE cartridge,eluted with ethyl acetate.The separation of analytes was carried out on a Shim-pack XR-ODS Ⅲ C18 column(2.0 mm×50 mm,1.6 μm) using mobile phases of 0.1%(by volume) formic acid in ultrapure water and methanol solution by gradient elutionA multiple reaction monitoring(MRM) scan mode and an enhanced product ion(EPI) scan mode as dependent in an information dependent acquisition(IDA) experiment were used in mass spectrometry acquisition．Lab-built EPI library and the internal standards were adopted for the identification and quantification．The results indicated that the calibration curve of SEM showed a good linearity(r=0.996) whithin the range of 0.5-40 μg/L.The limit of detection(LOD,S/N=3) for SEM was 0.10 μg/kg,and the limit of quantitation(LOQ,S/N=10) was 0.25 μg/kg．The average recoveries of SEM at four spiked levels of 0.25,0.5,2.0,10.0 μg/kg were in the range of 89.1%-112.8% with relative standard deviations(RSDs) of 1.4%-8.6%.With high sensitivity and good recovery,the proposed method was effectively used to identify and detect the residues of semicarbazide in flour and flour products.