Objective: To analyze the uterine artery and endometrial blood flow parameters by in patients with autoimmune-related recurrent spontaneous abortion (RSA) for providing clinical referene. Methods: A total of 48 patients with more than 2 consecutive miscarriages from March 2021 to March 2022 were selected. Transvaginal three-dimensional ultrasound were used to measure endometrial thickness, endometrial volume, hemodynamic parameters of the endometrium [vascularization index (VI) and vascularization flow index (VFI)], and blood flow parameters [resistance index (RI), pulsatility index (PI), and peak systolic to lowest diastolic velocity ratio (S/D)] of bilateral uterine arteries were assessed in 6-9 days after ovulation. According to the autoimmune-related indexes（antinuclear antibody， anti-cardiolipin antibody、， beta 2 glycoprotein Ⅰ, anti-double strand DNA antibody）, patients were divided into observation group and control group. Patients with all negative results were classified as non-autoimmune-related RSA (control group), while those with one or more abnormal indexes were considered RSA (observation group). Ultrasonographic parameters were compared between the two groups, and receiver operating characteristic (ROC) curves were used to evaluate the predictive value of ultrasonographic parameters for autoimmune-related RSA. Results: Autoimmune-related RSA accounted for 25% of clinically recurrent miscarriages. The VI and VFI values in the observation group were lower than those in the control group（P=0.005,0.017）. The average levels of PI and RI of bilateral uterine arteries in the observation group were significantly higher than those in the control group（P≤0.001,0.001）.There was no statistical difference in endometrial thickness and endometrial volume between the two groups. ROC curve analysis showed that uterine artery PI > 2.895, RI > 0.885, endometrial VI < 1.518%, and VFI < 0.140 predicted autoimmune-related RSA with area under the curve (AUC) values of 0.738,0.746,0.809,0.774，respectively. Conclusions: Compared to other RSA cases, patients with autoimmune-related RSA have increased uterine artery PI and RI values and reduced endometrial blood flow perfusion. Clinicians should be vigilant in screening for autoimmune-related indexes in such patients during clinical ultrasound examinations.