Abstract: This work focused on the quality of milk in cold chain. The relationship between quality and storage temperature and time on milk was investigated by biochemical means. The curve of TTT (Time-Temperature-Tolerance) was obtained from biochemical results. A Time-Temperature Indicator(TTI) to predict shelf life of milk has been developed by using single chip microprocessors. The results show that the higher the storage temperature and the longer the storage period, the more TBC (total bacterial count) and the lower freshness of milk. The remaining shelf life of milk was obtained by the variational temperature test, whose difference of results between measurement and biochemical analysis is less than 0.5 d. The TTI will alarm when abnormal condition that the remaining shelf life is less than 1 d occurs.