Abstract: [ Objective ]To investigate the effect of 17β-estradiol （E2） on mRNA expression levels of the [~-defensin-2 （SBD-2） in ovine oviduct epithelial ceils in vitro. [Method ]The primary ovine oviduct epithelial cells were isolated and subeuhured to 2nd passage. The 2nd passage cells were divided into five groups and were treated with 10^-6 tool/L, 10^-7 mol/L, 10^-8mol/L, 10-9 mol/L and 10^-10 mol/L of E2, respectively. The mRNA expression levels of the β-defensin-2 （SBD-2） of ovine oviduct epithelial cells were determined at 2^th h, 6^th h, 12^th, 24^th and 48^th after they were treated with different concentration of E2 by real-time RT- PCR, respectively. The blank control groups were also included in each E2 treated groups for each detection time. [ Results ] The mRNA expression of SBD-2 of ovine oviduct epithelial cells reached the extreme level when they were treated with E2 of 104 mol/L for 6 h and was significantly upregulated compared with the control（P〈0.01 ）, and the mRNA expression of the SBD-2 of the cells were also upregulated when they were treated with E2 of 10^-10 mol/L for 24 h and 48 h. The expression of the SBD-2 of the cells showed a gradual decrement trend with the increase of E2 concentration. [ Conclusion 3 It was indicated that the mRNA expression of SBD-2 of ovine oviduct epithelial cells can be upregnlated by specific concentration of E2 for certain time, and the effect of E2 on the expression of the SBD-2 of ovine oviduct epithelial cells showed a time effect and dose-dependent manner.