Theoretical and experimental vibration spectra of biochanin A in frequency range from 0.5 to 2.4 THz are investigated. Under room temperature and vacuum conditions, the absorption peaks were observed at 0.86, 1.15, 1.60, 1.74, 2.12 and 2.28 THz. In parallel with experimental study, 6-31G* basis set and density functional theory (DFT) are applied to obtain structure and vibrational frequencies of isolated genistein molecule at gas phase. The observed vibrational spectra are assigned according to DFT calculations. Results show that theoretical calculations are in good agreement with experimental data. The observed vibrational peaks in frequency range of 0.5~2.4 THz are mainly induced by collected vibrations of molecule. The research is helpful to understand the role of biochanin A in biological reactions.