Ultra-performance liquid chromatography (UPLC) coupled to photodiode array detection (PDA) and electrospray ionization (ESI) tandem mass spectrometry (MS) methods was developed to separate and characterize the chemical components in licorice. Pure ultraviolet (UV) spectra were extracted using chemometric methods, and pure mass spectra were obtained using rankmap analysis. After the acquirement of the pure mass spectra, the isotopic structure peaks of molecular ions were optimized using Origin software, which could provide some help for the qualitative analysis. Pure mass spectra could also provide the correct parent ion for further tandem MS analysis. Finally, sixty compounds were identified.