To investigate the expression change and location of transforming growth factor-beta1(TGF- β1) at uterus and placenta in the course of pregnancy and the effects of interferon gamma (IFNγ) on its expression, the expression of TGF-β1 was examined in uterus and placenta in different stages of gestation by methods of RT-PCR, Western blot, and immunohistochemistry respectively. And RT-PCR was used to analyze the expression of TGF-β1 mRNA after injecting different dose of IFNγ. Experimental results indicated that the expression of TGF-β1 mRNA and TGF-β1 protein were detected in uterus and placenta in every stage of gestation. The analysis of semie-quantitative RT-PCR that showed the expression of TGF-β1 mRNA was increasing gradually at uterus during the early stage of gestation (D1~D9). The expression of TGF-β1 in pre-implantation (D4) period was lower than that in implantation (D6) period and post-implantation (D9) period. The expression in post-implantation (D9) period is highest at uterus during gestation. With the process of gestation, the expression of TGF-β1 decreased significantly at uterus during mid-stage (D15) and late stage (D19) of gestation. The expression of TGF-β1 at placenta kept increasing in the course of pregnancy. The expression of TGF-β1 at mid-stage placenta (D15) was significantly higher (P<0.01) compared with that at early stage placenta (D9) and the expression of TGF-β1 at late-stage placenta D19) was significantly higher (P<0.01) compared with that at mid-stage placenta (D15). The analysis of immunohistochemistry indicated TGF-β1 mostly expressed at decidua during early stage of gestation and at trophoblast during mid-stage and late stage of gestation. After injecting exceeding normal concentration IFNγ by vaginal muscular, the expression of TGF-β1 was downregulated at uterus and placenta of pregnant rat.The results suggested that the expression of TGF-β1 was dynamic and spatio-temporal characteristics in uterus and placenta during gestation. IFNγ affected the expression of TGF-β1 at uterus and placenta in the course of pregnancy.