Objective A high performance liquid chromatography coupled to mass spectrometry (UPLC-MS/MS) method was developed for the determination of four mycotoxins in grain products such as bread, steamed bun and biscuit. MethodsSamples were extracted with acetonitrile-water (84∶16, V/V), then was purified by QuEChERS approach. UPLC separation was achieved by using BDS HYPERSIL C₁₈ (4.6 mm×100 mm, 2.4 μm) chromatographic column by gradient elution at a flow rate of 300 μl/min with methanol and acetate buffer as the mobile phase. The detection was carried out by negative electrospray ionization (ESI-) mass spectrometry in multiple reaction monitoring mode (MRM). Matrix-matched calibration was used for the quantification. The limits of detection, quantification, accuracy and precision of the method were evaluated. The method was used for detecting four mycotoxins in 60 different grains from the market. Results Under optimized condition, four mycotoxins had good linear relationships in the certain correlation ranges with the correlation coefficients all above 0.999. The average recoveries of 4 mycotoxins at three spiked levels ranged from 81.8% to 98.2% with relative standard deviations of 5.6%-9.3%. Four mycotoxins were detected in the 60 market samples. Deoxynivalenol (DON) was detected in all samples with the concentrations of 15.2-960 μg/kg, the other 3 mycotoxins were not detected. Conclusion The method was more simple and lower cost than the national standard method and the national food safety risk monitoring method, with fast speed, high sensitivity and good reproducibility, which improve the national food safety risk monitoring method.