Abstract: According to the method of NY/T 1680－2009 “Determination of carbendazim and other 3 benzimidazoles in vegetable and fruit by HPLC”,the mathematical model was established and used to evaluate the uncertainty in the measurement of carbendazim residue in apple.Every link of sample pretreatment and HPLC determination was analyzed,and then the uncertainty components were calculated on the basis of mathematical model.The determination result showed that concentration of carbendazim residue in sample was 0.23 mg/kg.The uncertainty in measurement of carbendazim residue mainly originated from recovery rate in parallel determination of samplesolution by HPLC,dilution process of samplesolution,extraction and purification of sample.Moreover,other processes,such as preparation,detection and extraction of standardsolution by HPLC,had some influence on the uncertainty.When the confidence probability was 95%,the extended uncertainty in measurement of carbendazim residue in apple by HPLC was 0.02 mg/kg.So the carbendazim residue in test sample can be expressed as (0.23±0.02) mg/kg (k=2) in case that the distribution of residue in apple be not considered at this circumstance.