Objective: To evaluate the changes of main quality indexes of bulk and final product of haemophilus influenzae type b( Hib) conjugate vaccine using CRM197,an avirulent mutant of diphtheria toxin as carrier protein under various conditions for storage and provide a reference for the determination of condition for storage and validity period of the vaccine.Methods: The bulk of Hib conjugate was stored sep. at 2 ∼ 8 °C for3,6 and 12 mo,at 20 ∼ 25 °C for 4 and 8 wk,and at 37 °C for 2,4 and 6 wk,while the final product was stored at 2 ∼ 8 °C for 6,12,18,24,30 and 36 mo,at 20 ∼ 25 °C for 6 and 12 mo,and at 37 °C for1,3,6 and 9 mo.Then the main quality indexes,such as polysaccharide content,free polysaccharide content,protein content,ratio of carbohydrate/protein,free protein content,p H value,endotoxin detection,and mol. weight,were determinedResults: All the quality indexes of bulk of Hib met the relevant requirements after storage at 2 ∼ 8 °C for 12 mo,at 20 ∼ 25 °C for 8 wk and at 37 °C for 6 wk.All the quality indexes of final product met the relevant requirements after storage at 2 ∼ 8 °C for 36 mo,at 20 ∼ 25 °C for 12 mo and at 35 ∼ 37 °C for 6 mo.Conclusion: Both the bulk and final product of Hib conjugate vaccine using CRM197 as carrier showed high stability.