Abstract: Objective: To detect the effect of nimesulide and Sulindac on the expression of iNOS, NF-κ B and to explore the significance of this effect in the antitumor process of NSAIDs. Methods: SGC-7901 cells were cultured in different concentrations of nimesulide and sulindac for about 48 h and the expression of iNOS and NF-κ B in tumor cell was detected with Power vision^TM immunohistochemical method and western-blot analysis, while the content of TNOS、iNOS、NO in SGC-7901 cells was detected by biochemistry method, respectively. Results: Compared to the negative control group, the expression rate of NF-κ B, iNOS and the content of TNOS, iNOS, NO in 100, 200μmol/L nimesulide and 0.6, 1.2mmol/L Sulindac group were significantly decreased (P<0.05). There was a positive correlationship between the expression of NF-κ B and of iNOS. Conclusions: Nimesulide and sulindac show the inhibitory effects on the expression of NF-κ B and iNOS in human gastric carcinoma SGC7901 cells and this may play some roles in the anti-tumor process of Sulindac and nimesulide. Inhibition of the expression of iNOS may result in the inhibitory effect on NF-κ B.