A rapid method for the detection of rapeseed polyphenols (Canolol) in rapeseed oil was studied. A normal phase high performance liquid chromatography (NP-HPLC) method for the determination of Canolol was established. The Canolol in rapeseed oil were determined by using hexane to isopropanol (volume ratio 96∶4) as the mobile phase with the flow rate of 0.8 mL/min, column temperature of 30 ℃, fluorescence detector with excitation wavelength of 298 nm and emission wavelength of 325 nm. The linear correlation coefficient was above 0.999, and the recovery rate was between 96% and 110%. The detection limit of the instrument was 15 ng/mL, and the precision was better than 3%. The method has the advantages of simple operation, short analysis time, high accuracy and less environmental pollution. The optimized detection method was used to determine the rapeseed oil samples from 90 different varieties of rapeseed in different regions of China. The content of Canolol ranged from 190 mg/kg to 2 246 mg/kg. At the same time, different types of vegetable oils randomly purchased from the market were tested. The results showed that Canolol was a unique component in rapeseed oil by processing of heated screw-pressing.