An analytical method was established for the determination of baicalin and dictamnine in cosmetics by ultra performance liquid chromatography（UPLC）.Different types of samples were extracted by ultrasonication with methanol-phosphate buffer solution（9∶1，pH 2.5）.After demulsified by addition of appropriate NaCl,sample extracts were separated on an ACQUITY UPLCTM CSH C18 column（2.1 mm×100 mm,1.7 μm,Waters） by gradient elution using acetonitrile-0.1% fomic acid as mobile phase.The detective wavelength was 314 nm.For the target compouds,the calibration curves were linear in the range of 0.05-10 mg/L,with correlation coefficients more than 0.999.The method limits of detection（LOD,S/N=3） for both were 0.3 mg/kg.The average recoveries ranged from 92.2% to 103.1% with relative standard deviations（RSDs） less than 4%.Meanwhile,the confirmed method was developed by ultra-performance liquid chromatography quadrupole-time-of-flight mass spectrometric（UPLC-Q-TOF） with a parent ion and a product ion monitored.The accuracy of molecular ions was less than 5 ppm.By this method,a degradation product of baicalin was also identified.