Abstract: A method for determination of fenbutatin oxide residue in citrus fruit and soil was established based on gas chromatograph with electron capture detector (GC-ECD).Residues were extracted from samples with acetonitrile,followed by clean-up using neutral alumina column and determination using GC-ECD.Average fortified recoveries in samples were found at the range of 92%-98% at fortified levels from 0.5 mg/kg to 5.0 mg/kg,with relative standard deviations of 5.8%-8.7% (n=5).The method detection limit (MDL) of fenbutatin oxide was 1×10-10g,and the limit of quantification (LOQ) of fenbutatin oxide in samples was 0.5 mg/kg.No interferences were found by using this method for blank samples.The current method need no special instrument and can meet the requirements of pesticide residue analysis on accuracy,sensitivity and precision.In conclusion,this method is suitable for the analysis of fenbutatin oxide residue in citrus fruit and soil.The study indicated that the half-life of fenbutatin oxide in citrus fruit and soil was 9-14 days and 9-11 days.Fenbutatin oxide belongs to the easily degradable pesticide in citrus fruit and soil.