To explore the efficacy of the blood flow parameters of patients by three-dimensional transvaginal ultrasound (3D-TVS) for diagnosing their intrauterine adhesion (IUA), and to study the correlation between the blood flow parameters of the women and the severity of their IUA. Methods: 96 women with IUA were enrolled in study group between March 2019 and December 2021, and other 82 normal women who underwent physical examination were enrolled in control group during the same period. All these women had undergone 3D-TVS examination. In study group, the diagnosis accuracy of 3D-TVS for IUA was evaluated and the diagnostic efficiency was analyzed based on the hysteroscopy results of IUA as the golden standard. The blood flow parameters, such as endometrial vascular index (VI), vasularization flow index (VFI), flow index (FI), and endometrial volume (EV) of the women in both groups were detected. According to grading standard of IUA, the women in the study group included the women with grade I grade of IUA in group A, the women with gradeⅡ of IUA in group B, and the women with grade III of IUA in group C. The correlation of the blood flow parameters values of the women with IUA and their different grade of IUA was analyzed. Results: Among 96 women with IUA, 91 cases were diagnosed as IUA by 3D-TVS, with the accuracy of 94.8%, the sensitivity of 94.8%, the specificity of 97.6%, the positive predictive value of 97.9%, and the negative predictive value of 94.1%. The values of EV, FI, VFI, and VFI of the women in the study group were significantly lower than those of the women in the control group (P＜0.05), and which of the women in group A, in group B, and in group C had decreased gradually (P＜0.05). The values of EV, FI, VFI, and VFI of the women with IUA were negatively correlated with their IUA grading (P＜0.05). Conclusion: 3D-TVS examination of the women for diagnosing their IUA has higher efficacy. The blood flow parameters values of the women by 3D-TVS are negatively correlated with their severity of IUA, and which can be applied in the disease assessment of IUA.