Abstract: Objective: To analyze the predictive value of transabdominal ultrasonography in the diagnosis of the thickness of lower segment of the anterior wall of the uterine scar in the middle and late stage of pregnancy on the way of delivery and the occurrence of uterine rupture. Method: Chose 92 cases of pregnant women with cesarean section at the second trimester or at the third trimester who gave birth in our hospital between November 2015 and August 2017. Used abdominal ultrasound to observe the thickness and structure of the lower uterine segment. According to the image and the thickness of lower segment of the anterior wall, the subjects would be divided into grade Ⅰ scar group (44 cases), grade Ⅱ scar group (25 cases) and grade Ⅲ scar group (23 cases). Compared the changes in the thickness of lower segment of the anterior wall varying with gestational age and the outcome of pregnancy of the three groups. Results: With the increase of pregnant weeks, the thickness of lower segment the uterine anterior wall of the grade Ⅰ scar group was obviously higher than that of the grade Ⅱ scar group and the grade Ⅲ scar group (<i<P</i<<0.05). The thickness of the lower segment of uterine anterior wall in the three groups was significantly thinner, and there were statistically significant differences in the different gestational weeks (<i<P</i<<0.05). With the increase of scar grade, the success rate of vaginal trial production decreased gradually, and the incidence of threatened uterine rupture was significantly increased. Moreover, there was statistically significant difference between groups (<i<P</i<<0.05). Conclusion: Transabdominal ultrasonography can show the muscularis of the lower uterine segment and the thickness of the lower segment of anterior wall of the uterine scar at the second and third trimester. Therefore, it can be used to provide valuable diagnostic information for the clinical vaginal trial production and the threatened uterine rupture.