Abstract: In order to explore the fetal-protecting effect of Chinese medicine Angelica sinensis on abortion mice, and the effect of Angelica sinensis on local cellular immunity in uterus of mice during pregnancy, pregnancy occurred in mice through natural mating, and mifepristone（RU486） was used to induce abortion in mice to make experimental animal abortion model. Pregnant mice were randomly divided into 3 groups of 10 mice each. Mice in the blank control group（group A） were given purified water every day, 0.5 mL per mice on the 1 st to 7 th day of pregnancy, and 0.1 mL per mice was subcutaneously injected with propylene glycol through the neck on the 7 th day of pregnancy. Mice in the abortion model group（group B） were given purified water daily on the 1 st to 7 th day of pregnancy, 0.5 mL per mice, and on the 7 th day of pregnancy, RU486 was subcutaneously injected through the neck, 0.1 mL（0.025 mg） per mice. Mice in Angelica sinensis treatment group（group C） were given Angelica decoction, 0.5 mL（equivalent to 0.5 g crude drug）per mice every day from the 1 st to 7 th day of pregnancy, and on the 7 th day of pregnancy, RU486 was injected subcutaneously through the neck, 0.1 mL per mice. To count the proportion of embryos lost in aborted mice, the fetal-protecting effect of traditional Chinese medicine was evaluated. Flow cytometry was used to detect the proportion of Th17 cells and Treg cells in the uterine tissue of aborted and successfully pregnant mice, and the contents of interleukin-6（IL-6）, interleukin-10（IL-10） and transforming growth factor-β（TGF-β） in mouse uterine tissue were determined. The results showed that after RU486 model was established, the abortion rate of the mice in the group C decreased to 40%, the embryo absorption rate decreased to 34.92%, and the proportion of Th17 cells in the uterine tissue was（1.52±0.30）%, which was significantly lower than group B（P＜0.01）. The proportion of Treg cells was（10.21±1.18）%, which was significantly higher than that of the model group（P＜0.01）. Th17/Treg value was 0.15, which was significantly lower than group B（P＜0.01）; IL-6 content in uterine tissue was（5.30±1.16） ng/mL, which was significantly lower than group B（P＜0.01）; the content of IL-10 reached（122.20±43.15） pg/mL, which was significantly higher than that in group B（P＜0.01）, but the content of TGF-β was not significantly different from that in group B（P＞0.05）. The results suggested that Chinese medicine Angelica sinensis could regulate the differentiation of local immune cells in the uterus and the contents of some pregnancy-related cytokines, and adjust the local immune status of the pregnant uterus. By local immunomodulation of the uterus, the immune response was biased towards Treg cells, and through Treg-mediated immunosuppression, immunity was favored to maintain the pregnancy process.