Objective:To investigate the effect of naringenin on TGF-β1/Smad pathway in human bronchial epithelial cells. Methods:HBE cells were divided into the control group,the TGF-β1 group and the naringenin group. The naringenin groups were incubated with different doses of naringenin (25,50 and 100 mol/L) for 2 h. Then the naringenin group and the TGF-β1 group were incubated with TGF-β1. After 2 h,we determined the PAI-1 mRNA level by real time-PCR. After incubated with TGF-β1 for 30 min,we detected Smad2 and Smad2 phosphorylation by Western. Smad2 nuclear translocation was analyzed by indirect immunofluorescent staining. Results:Compared with the control group,the expression of PAI-1 mRNA was significantly increasing in HBE cells stimulated with TGF-β1. Naringenin has inhibitory effects on the expression of PAI-1 mRNA. The totle of Smad2 was similar in different groups. Compared with the control group,phosphorylated-Smad2 was increasing in the TGF-β1 group. Naringenin could significantly inhibit the Smad2 phosphorylation. Immunofluorescent staining showed that the nuclear content of Smad2 in the TGF-β1 group was increased,and in the naringenin group(100 -滋mol/L) was decreased. Conclusion:Naringenin may inhibit TGF-β1/Smad through attenuated Smad2 phosphorylation and suppressed the nuclear content of Smad2 in human bronchial epithelial cells.