A method was developed for the determination of 4 aflatoxins and 11 pesticide residues in peanut by ultrahigh performance liquid chromatography-quadrupole/electrostatic field orbitrap high resolution mass spectrometry（UPLC-HRMS）.The samples were extracted with acetonitrile-water-acetic acid（84∶15∶1，by volume）,and the extracts were cleaned up with 1.0 g MgSO4,100 mg PSA and 400 mg C18.The analytes were separated on a Hypersil Gold C18 column（100 mm×2.1 mm，1.9 μm）,and quantified by UPLC-HRMS.Results showed that 4 aflatoxins and 11 pesticide residues had good linear relationships in their respective mass concentration ranges with their correlation coefficients（r2）more than 0.996.The limits of quantitation（LOQs）of the method ranged from 0.25 μg/kg to 1.0 μg/kg.The spiked recoveries for 4 aflatoxins and 11 pesticide residues at three spiked levels ranged from 79.4%to 120%with relative standard deviations（RSD,n=6） of 4.2%-10%.With the advantages of high sensitivity and reliability,the method was suitable for the simultaneous determination of 4 aflatoxins and 11 pesticide residues in peanut.