The T-box transcription factor protein eomesodermin (Eomes) is known for both homeostasis and function of effector and memory CD8+T cells. However, much less is known about the functional regulation of Eomes on CD8+ T cells during pregnancy. In the present study, we concluded the higher Eomes expression dCD8+T cells during normal early pregnancy. The number of Eomes+dCD8+T cells decreased in miscarriage. This Eomes+dCD8+T cell subset also expressed less growth-promoting factors, shifted toward pro-inflammatory phenotype in miscarriage. Primary Trophoblasts and HTR8/SVneo cell line could increase Eomes expression of dCD8+T cells from both normal early pregnancy and miscarriage, which might provide a new strategy for therapy to promote maternal-fetal tolerance and prevent pregnancy loss. These findings indicated that Eomes might be promising early warming targets of miscarriage. In addition, this study suggested that the reproductive safety must be a criterion considered in modulating the dose and function of Eomes in CD8+T cells to reverse T cell exhaustion.