A novel fluorimetric method for determination of paeonol,an active component of Chinese herbal medicine,is proposed.The method is based on the reaction of paeonol with aluminum ion in pH 4.4 HAc-NaAc buffer to form a fluorescent Al(Ⅲ)-paeonol complex.The maximum excitation wavelength and emission wavelength of the complex were 296 nm and 455 nm,respectively.The fuorescence quantum yield of the complex was determined to be 0.053 at an excitation wavelength of 296 nm.A linear calibration curve covered the concentration range 0.017-1.2μg/mL.The method has been applied to the analysis of paeonol in medicinal crop Cynanchi Paniculati Radix(Xuchangqing),and the results demonstrated that this method can be used for quality evaluation of crude drug Xuchangqing.