Terahertz (THz) spectroscopy has fingerprint features for many bio-molecules with frequency between infrared and microwave covering the vibrational models of a great number of materials. In this study, THz-TDS was used to detect the preserved and bad meat. And the absorption coefficient indices of bad meat and preserved meat were measured in the range of 0.2–1.0 THz. The result shows that there are differences of pork tissue in both time domain and absorption coefficient in the process of deterioration. Then differences between preserved and bad meat were also presented. In order to investigate the relationship between the terahertz characteristics and meat quality, the changes of water content and material in the samples were also discussed. This work supplies reference for the application of THz technology in meat quality detection.