Abstract: A high performance liquid chromatography method was used to determine formaldehyde in fruits and vegetables by o-( 2,3,4,5,6-pentafluorobenzyl) hydroxylamine hydrochloride derived with formaldehyde,Samples was directly extracted and derived at a temperature of 70 ℃ under the conditions of ultrasonic 30 min,then monitored by liquid chromatography after centrifugation and purified and quantified using the external standard method.The detection was performed on a XDB-C₁₈ column( 4.6 mm × 250 mm,5 μm) in an isocratic elution mode using a mobile phase consisting of acetonitrile and water( 70∶ 30,v/v) at a flow rate of 1.0 m L/min,the column temperature was 40 ℃ and detection wavelength was 210 nm. The results showed that the quantification limit of the method was 0.114 mg/kg,with a good linear relationship between 0.57~57 mg/kg.The average recovery rate were 82.3% ~94.1%,with RSD of 4.0% ~8.1%( n = 6).The method was simple,stability,low detection limits and suitable for the determination formaldehyde in fruits and vegetables.