Objective:To investigate the inhibition effect of proliferation of gastric cancer cell line SGC7901 treated with selective cyclooxgenase 2（COX-2）inhibitor

nimesulide

and the probable mechanism of cell signal transduction.Methods: SGC7901 cells were treated with nimesulide.MTT assay was used to measure the cell proliferation;Flow cytometry was used to detect cell cycle and apoptosis.The protein expression related to STAT3 signaling pathway in SGC7901 cells was examined by Western blot.Results:The growth of gastric cancer cells was obviously inhibited in a time-and dose-dependent manner after nimesulide treatment;the percentage of apoptosis was increased significantly（P

<

0.05）;the proportion of SGC7901 in G

0

/G

1

phase was hoisted significantly（P

<

0.05）;Western blot analysis showed that:the protein expression of phosphorylated STAT3（P-STAT3）

CyclinD1

Bcl-2 in SGC-7901 cells was decreased significantly（P

<

0.05）.Conclusions:The proliferation of gastric cancer cell line SGC7901 could be inhibited;the course of cell cycle could be prevented;cell apoptosis could be induced by nimesulide through down-regulating the protein expression of P-STAT3

CyclinD1

Bcl-2

which was probably one of its molecular mechanisms.