Abstract: To investigate the effect of different storage temperatures on the viability of vacuum freeze-dried fermenting agent Lactobacillus fermentum grx07,the survival rate,viable cell count,water activity,fermentation activity and the key enzyme activities of vitality related(lactate dehydrogenase,β-galactosidase,ATPase)were measured at 20,4 and -20℃,respectively. The results showed that the three-month survival rate of starter grx07 was less than 1% at 20℃,while the survival rates was seperately 4.45% and 51.05% at 4 and -20℃ for 12 months. The number of viable cells stored at -20℃ for 12 months were still reached to 3.78×10¹¹ cfu/g,the water activity of the powder was 0.210,and the fermentation pH was 4.30. Moreover,the activities of lactate dehydrogenase,β-galactosidase,and ATPase were separately 80.24%,74.60%,87.10% of that prior to the storage. Therefore,the suitable temperature for long-term storage of the vacuum freeze-dried starter grx07 was -20℃.