To observe the influence of ultrasound intervention and intramuscular injection of methotrexate on the blood flow index of uterine scar pregnancy location and stress factors of women with cesarean scar pregnancy (CSP). Methods: 66 women with CSP were selected as the research objects from January 2019 to May 2020, and were divided into control group (33 women with intramuscularly methotrexate injection) and observation group (33 women with methotrexate injection in CSP location under ultrasound). The clinical efficacy, blood flow index, such as pulsatility index (PI), vascular index (FI), maximum flow rate (Vmax), and stress factors, such as pregnancy-associated protein (PAPP-A), inhibin-A (INH-A), vascular endothelial growth factor (VEGF) of women were compared between the two groups. Results: The total effective rate of women in the observation group (93.9%) was significant higher than that (72.7%) of women in the control group (P<0.05). The values of PI, FI, and Vmax of women in the observation group after 3 days were 0.70±0.15, 0.08±0.04, and 10.38±3.65 cm/s, respectively, which were all significant lower than those of women in the control group (P<0.05), and the values of PI, FI, and Vmax of women in the observation group after 1 week were 0.50±0.13m, 0.03±0.01, and 7.40±2.60 cm/s, respectively, which were also significant lower than those of women in the control group (P<0.05). The PAPP-A, INH-A and VEGF levels of women in the observation group after 1 week treatment were 5.12±1.56 U/L, 2.01±0.58 pg/ml, and 122.36±10.02 ng/L, respectively, which were significant lower than those of women in the control group (P<0.05). Conclusion: Methotrexate injection in CSP location under ultrasound intervention for threading women with CSP has better efficacy, and has little effect on stress response and local blood flow index of CSP, which is benefit for the recovery of women after treatment.