Objective: To assess Superb micro vascular imaging (SMI) combined conventional ultrasonic application Value in diagnosing prenatal placenta accreta. Methods: A total of 59 patients with placenta accreta from 2016 September to 2018 August examined by routine ultrasound examination and SMI were retrospectively analyzed. And sixty patients without placental implantation clinically diagnosed after delivery were randomly selected. The boundary of the intrauterine lesions, the thickness of the myometrium, the blood vessels of the placenta implantation site were observed. To evaluate the value of these indexes in diagnosing prenatal placenta accreta.by receiver operating characteristic(ROC) curves. In addition, using the intra-operative diagnosis and the postoperative pathological results as the golden standard to compare, evaluate and analyze application value of the conventional ultrasound examination and the conventional ultrasound examination combined with SMI examination in diagnosis of uterine placenta implantation. Results: The placental implantation group was compared with the non-placental implantation group, the incidence rate of the unclear boundary of the myometrium, the myometrium becoming thinner or disappeared, the interlace and disorder of blood vessels of the placenta implantation site increased significantly in the pregnant women with placenta implantation, there were statistically significant differences(P＜0.01). The value of area under the curve of the aggregative diagnosis in placental implantation was 0.936 according to the operating characteristic curves. The accuracy, sensitivity and specificity rating of prenatal routine ultrasound diagnosis in uterine placenta implantation was79.83%、78.00%、81.67% respectively. And, these respective ratings of the conventional ultrasound examination combined with SMI examination were 89.92%、89.83%、90.00%. Conclusion: SMI can reflect the lower velocity blood flow in placenta accurately. The extent and the range of the placenta implantation can be evaluated combining conventional ultrasound. It has the important clinical value in diagnosing prenatal placenta accrete timely.