The spectral characteristics of potassium sorbate in milk powder in the range of 0.2-2.0 THz have been measured with THz time-domain spectroscopy(THz-TDS).Its absorption and refraction spectra are obtained at room temperature in nitrogen atmosphere.The results showed that potassium sorbate at 0.98 THz obvious characteristic absorption peak.The simple liner regression(SLR)model was taken to analyze the content of potassium sorbate in milk powder.The results showed that the absorption coefficient increases as the mixture potassium sorbate increases.The research is important to food qual ity and safety testing.