Objective To study the effect of selective COX-2 inhibitor NS-398 on IL-1α and TNF a expression in HaCaT cells induced by UVA/UVB,and further to explore the mechanism on anti human skin photo damage. Methods The subcuhured HaCaT cells were divided into three groups:simple illuminated group was exposed to UVA/UVB directly,NS-398 interfered group was exposed to UVA/UVB after being treated with NS-398 in different concentrations,and the control group was cultured in normal without any treatment.The expression of IL -1α and TNF-α in supernarant was detected by ELISA kit.Results The level of IL-1α and TNF-α expression in supernatant from simple illuminated group was remarkably higher than that in the control group,NS-398 interfered group showed much lower level than the simple illuminated one,and the expression of IL-1α and TNF-α was dependent on the concentration of NS-398.Conclusions NS-398 can reduce IL-1α and TNF-α expression in HaCaT cells induced by ultraviolet rays,suggesting the possibility of anti human skin photo- damage effect.