The absorption spectra from 0.2 to 1.7 THz of five water-acetone mixtures, whose concentrations are 0%, 25%, 50%, 75%, and 100%, has been investigated by THz time-domain spectroscopy (THz-TDS). The result indicates that of acetone solutions with different concentrations have different absorption for THz radiation, which is analyzed and attributed to the variation of the hydrogen bond. Furthermore, we also find the absorption of the water-acetone mixture almost linearly increases with the increase of water concentration in the THz range.