Objective To investigate the inhibitory effect on human ACHN cell line and its mice xenograft by using interferon α-1b combined with cyclooxygenase-2 inhibitor and the relevant mechanism in vitro and vivo experiment .Methods ACHN cell and the xenograft mice were devided into 4 groups(IFN-α1b,NS398,IFNα-1b+NS398 and control group).The inhibitory effects were tested by CCK8(Cell Counting Kit 8)assay after AHCN were treated for 24 h and 48 h.The expression of bcl-xl and COX-2 were detected by Western blot .The vol-ume of the xenografts of ACHN cell line and testing the expression of VEGF in xenografts were measured by immunohistochemistry assay .Re-sults Both IFNα-1b and NS398 exerted inhibitory effects on ACHN and this effects showed a rising trend with a increasing concentration of drugs.The combined group was more significant than monotherapy group (P<0.05).Western blot assay showed that IFNα-1b and NS398 downregulated the expression of bcl-xl and COX-2 in ACHN.The combined group was more significant than monotherapy group (P<0.05). The combined group has the greatest inhibitory effects on the xenografts of ACHN cell line compared with monotherapy group and control group(P<0.05).The expression of VEGF in tumor was obiviously inhibited in combined group compared with monotherapy group and con -trol group (P<0.05).Conclusion IFNα-1b combined with NS398 can inhibit the proliferation of ACHN and suppress the tumor growth .