Abstract: A simple, fast, and environmental-friendly determination method of alachlor residue in corn was established using QuEChERS- HPLC equipped with UV detector. Samples were extracted by a little acetonitrile, purified by N- propyl ethylenediamine (PSA) and graphitized carbon black (GCB). The concentration of alachlor was detected by HPLC-UV. The analytical column was C18 (250 mm×4.6 mm×5.0 μm) and the mobile phase was acetonitrile mixed with water (70:30 V/V). With a significant linear relation (R2≥0.994) of standard samples measured by this method, the average recovery rates of different alachlor doses (0.2-10 mg/kg) were 96.7%-113.8% and RSD were 3.2%-15.3%. The limit of detection and the limit of quantitation were 0.015 mg/kg and 0.05 mg/kg respectively. The accuracy, sensitivity and precision of this method can meet the requirement of pesticide residue analysis.