Objective To investigate the contamination of 4 kinds of alternaria toxins in grains in Shaanxi Province and evaluate the risk to the health of dietary exposure.Methods A total of 171 samples of wheat flour， rice and corn grits were randomly collected in circulation in 2022. Four kinds of alternaria toxins were determined by ultra high performance liquid chromatography tandem mass spectrometry. The health risk of altemaria toxins in grains were evaluated based on the threshold of toxicological concern method.Results The average contents of alternariol， alternariol monomethyl ether， tenuazonic acid and tentoxin were 0.128， 0.461， 15.3 and 1.67 μg/kg in grains， with the detection rates of 8.19， 56.73， 57.31 and 38.01%， respectively. There was a significant correlation between tenuazonic acid and tentoxin contents in wheat flour. The alternariol average dietary exposure is 0.64 ng/（kg·BW·d）， below the corresponding TTC values. The alternariol P_97.5 dietary exposure is 4.62 ng/（kg·BW·d）， above the corresponding TTC values. The alternariol monomethyl ether average and P_97.5 dietary exposures are 3.45 and 17.8 ng/（kg·BW·d）， above the corresponding TTC values. The tenuazonic acid average and P_97.5 dietary exposures are 144 and 336 ng/（kg·BW·d）， below the corresponding TTC values. The tentoxin average and P_97.5 dietary exposures are 16.7 and 32.6 ng/（kg·BW·d）， below the corresponding TTC values.Conclusion The grains were contaminated by 4 kinds of alternaria toxins to different degrees in Shaanxi Province. The dietary exposure levels of alternariol and alternariol monomethyl ether in grains exceed the TTC values， and children aged from 2 to 7 years old were higher exposure. Tenuazonic acid and tentoxin were lower dietary exposure.