An UPLC Quadrupole Orbitrap high resolution mass Spectrometry method for accurate quantification of aflatoxins in grains and oils was established, which were purified by automatic immunoaffinity column. The sample was extracted with 84/16(V/V) acetonitrile/water and centrifuged. The supernatant was diluted 10 times with 0.1% PBST. Aflatoxin immunoaffinity column without background and recovery greater than 90% was chosen for purification automatically. UPLC-Quadrupole Orbitrap HRMS was used for quantitative analysis. Results showed that recoveries for aflatoxins were 84.7%~104.6%. The intra-day relative standard deviations were 1.7%~9.4%, and the intra-day precision were 0.7%~8.4%. The developed method can minimize the workload, improve work efficiency and avoid the result deviation caused by operation manually. It is suitable for the accurate determination of aflatoxins in grains and oils, and meet the requirement of the daily test and monitoring aflatoxins.