Abstract: To evaluate the medication safety of common herbicide chlortoluron, based on organic solvent solidliquid extraction method, through comparison of extraction recovery and oscillating time, the author set the extraction time as 2 hours and adopted chromatographic C18 separation and acetonitrile- water elution, to determine HPLC method for chlortoluron residue under 243 nm in corn plants, corn grain and soil. The method was proved to be an effective quantitative determination method of chlorotoluron in corn and soil, which was easily operated and of high recovery rate, with the minimum detectable quantity and minimum detectable concentration of chlortoluron to be 1.0×10- 3 ng and 0.001 mg/kg, respectively, and the recovery rate ranged from 90.4% to 108.8%.