Objective. To evaluate the changes of rectus abdominis thickness and inter-rectus distance before and after delivery with high-frequency ultrasound. Methods. A total of 148 pregnant women at 12 weeks of gestation who underwent prenatal examination in our hospital from January 2019 to March 2020 were selected, and 140 of them cooperated with rectus abdominis examination. According to the results of rectus abdominis examination 42 days after delivery, 97 patients were divided into the DRA group with rectus abdominis isolated and 43 patients were divided into the normal group with rectus abdominis not isolated. At 12 weeks, 24 weeks, and 37 weeks of pregnancy, 3 days and 42 days after delivery, the thickness and spacing of the left and right rectus abdominis muscle were measured by high-frequency ultrasound along the white linea at three positions: 5 cm above the navel, 3 cm below the umbilical edge, and 3 cm below the navel. Results. The thickness of rectus abdominis at 5 cm above the navel, 3 cm below the navel, and at the navel margin of the abdominal white line in the pregnant women of the two groups was gradually decreased with the increase of the pregnancy cycle and gradually recovered after delivery. At 42 days after delivery, the thickness of rectus abdominis in the DRA group was significantly lower than that in the normal group, which was 5 cm above the umbilicus, 3 cm below the umbilicus, and the umbilical margin of the abdominal white line (
P
<
0.05
). The space between rectus abdominis 5 cm above the navel, 3 cm below the navel, and the navel margin of the abdominal white line in the pregnant women of the two groups was gradually increased with the increase of the pregnancy cycle and gradually recovered after delivery. At 37 weeks of pregnancy, 3 days after delivery, and 42 days after delivery, the space of rectus abdominis along the umbilicus 5 cm above, 3 cm below the umbilicus, and the umbilicus border of the abdominal white line in the DRA group was significantly larger than that of the normal group (
P
<
0.05
). Conclusion. Ultrasound can accurately measure the inter-rectus distance and rectus thickness, accurately evaluate the degree of DRA, and realize the one-stop evaluation from prenatal diagnosis and prediction to postpartum rehabilitation monitoring, so as to intervene during pregnancy and reduce the risk of postpartum DRA.