【Abstract】Objective To investigate the relationship of expressions of cylooxygenase-2 (COX-2) and hypoxia-inducible factor-1α (HIF-1α) in hepatocelluar carcinoma (HCC) and the possible antineoplastic mechanism of selective COX-2 inhibitor. Methods The expressions of COX-2 and HIF-1α in 53 cases of HCC tissues were detected immunohistochemically. Western blot was employed to evaluate the effects of variant concentration of COX-2 inhibitor meloxicam on expression of HIF-1α in Cobaltchloridestimulated SMMC-7721 cell. ResultsOf 53 tumor tissues, the expression of COX-2 was 22/53 (41.5%) bly positive stained, 11/53 (20.8%) positive stained, and 20/53 (37.7%) negative stained. Meanwhile the expression of HIF-1α was 18/53 （34.0%） bly positive stained, 18/53 （34.0%）positive stained, 17/53（32.1%） negative stained. The expression of COX-2 was correlated positively with HIF-1α in HCC （r=0.440, P＜0.01）. The expression of HIF-1α increased sharply from 0.185±0.057 (no Cobaltchloride-stimulated) to 1.011±0.131 (Cobaltchloride-stimulated), and meloxicam could inhibit the expression of HIF-1α at either condition (P＜0.05). ConclusionMeloxicam could inhibit the expression of HIF-1α in a concentration-dependent manner in the Cobaltchloridestimulated SMMC-7721 cell. The antineoplastic activity of selective COX-2 inhibitor was possibly, at least in part, mediated by HIF-1α.