Abstract: Total volatile basic nitrogen (TVB-N) was the unique physical and chemical indicators to evaluate the freshness of meat in the national standard. The p-dimethylaminobenzaldehyde (PDAB) being chromogenic reagent, the relationship between the TVB-N content and its absorbance was studied. Colorimetric determination method of raw meat freshness was established. The results showed that 1mL of extraction from raw meat was added 1.8% (W/V) PDAB chromogenic agent 4.5mL, and concentrated hydrochloric acid 1.2mL, and distilled water 3.3mL, and heated for eight minutes in a water bath at 80℃. The relationship between the absorbance which was measured at 446 nm and TVB-N content of raw meat was linear. The method of colorimetric determination of raw meat freshness by PDAB was established, which was fast, stable, and easy to operate and with high precision and recovery. This might be one of the alternative for measuring freshness of raw meat in future national standards.