To study the effects of intrathecal injection of dexmedetomidine during cesarean section of women with mild preeclampsia on their anesthesia, PASS score, and neonates. Methods: The clinical data of 105 women with mild preeclampsia after cesarean section from June 2019 to June 2021 were selected in the study. According to the anaesthetic drugs used, these women were included 51 with basic anesthetics in control group, and 54 women with basic anesthetics combined with dexmedetomidine intrathecal injection in study group. The anesthesia effect (sensory block and motor block Bromage score), the sedation effect (PASS score at the time of skin incision, at the fetus delivery, and at the end of the operation), and the adverse reactions rate of the women, and the neonatal birth weight, Apgar score, and behavioral neurological assessment (NBNA) score were compared between the two groups. Results: The onset time of sensory block or motor block of the women in the study group was significantly shorter than that of the women in the control group, and the duration of sensory block or motor block of the women in the study group was significantly longer than that of the women in the control group.  The PASS scores of the women in both groups had increased firstly, and then had decreased after skin incision, and which of the women in the study group at the skin incision (0.68±0.17 points), at the fetus delivery (1.14±0.34 points), and at the end of the operation (0.56±0.19 points) were significantly lower than those (0.82±0.20 points, 1.55±0.38 points, and 0.73±0.21 points) of the women in the control group (all P＜0.05). There were no significant differences in adverse reactions rate (27.8% vs. 25.5%) of the women, and the neonatal birth weight, NBNA scores at 1h and 24h after born, and Apgar scores at 1min and 5min after born between the two groups (P＞0.05). Conclusion: 0.75% ropivacaine combined with intrathecal injection of dexmedetomidine during cesarean section of the women with mild preeclampsia can effectively improve their anesthesic and analgesic effect, the safety of which is acceptable, and with little impact on their neonates.