Abstract: The epithelial cell of the Mongolian sheep's fallopian tubes were cultured as in vitro model, different concentrations of progesterone (10^-6, 10^-7, 10^-8, 10^-9 and 10^-10 mol/L) were added in the culture, and then the relative expressions of sheep β-defensin-1 (sBD-1) mRNA were surveyed by real time PCR. The results showed that, compared with the control group, the relative expressions of sBD-1 mRNA added with 10^-6 and 10^-7 mol/L progesterone were significantly higher (P<0.05), and those of 10^-8 and 10^-9 mol/L groups were remarkably higher (P<0.01). However, there was no significant difference between 10^-10 mol/L group and control. Among groups added with progesterone, the sBD-1 mRNA expressions of 10^-8 and 10^-9 mol/L groups were markedly higher than that of 10^-10 mol/L group (P<0.01), but there was no difference among other added groups. The results indicated that progesterone promoted the relative expression of sBD-1 mRNA in the epithelial cell of the fallopian tubes within the indicated concentrations (10^-9-10^-6 mol/L). And the relative expression of sBD-1 mRNA was varied with the different concentrations of progesterone. In conclusion, the expression of β-defensin was related to progesterone in female reproductive tract.