Abstract: ObjectiveTo study the relationship between expression of Annexin A5 and the differentiation and metastasis of nasopharyngeal carcinoma (NPC）. Methods The expression of Annexin A5 in specimens of 65 of NPC, 18 of lymph node metastasizing NPC (LMNPC) and 20 of chronic rhinitis (CR) were detected by immunohistochemistry. The correlation between the expression of Annexin A5 and clinic factors was analyzed.The expression of Annexin A5 in NPC cell lines with differential differentiation degree and metastasis potency was detected by Western blot.Observe the change of invasive capability of NPC cells after the downregulation of Annexin A5 by siRNA. Results The positive ratio of Annexin A5 in NPC, LMNPC and CR were 84.6%(55/65), 94.4%(17/18) and 10.0%(2/20), respectively.There were significant difference in the expression of Annexin A5 between NPC and LMNPC, NPC and CR (P<0.05).There were correlation among the expression of Annexin A5 and histological type, regional meastasis, distant metastasis, clinic stage and recurrence (P<0.05).And was no relationship with ages and gender.There was relationship among expression of Annexin A5 and differentiation and metastasis of NPC.Downregulation of Annexin A5 can decrease the invasive capability of 5-8F cells. Conclusion There was relationship among the expression of Annexin A5 and the differentiation and metastasis of NPC, and could serve as a biomarker of differentiation, metastasis and prognosis in NPC.