Objective High-frequency ultrasound combined with shear wave elastography(SWE) was used to quantitatively evaluate inter-rectus distance, stiffness, and thickness of rectus abdominis, and to analyze the related factors of diastasis rectus abdominis(DRA) in postpartum women. Methods A total of 224 primiparas who underwent postpartum examination in the outpatient department of our hospital were selected. The thickness of rectus abdominis, inter-rectus distance, elastic modulus (E), and shear wave velocity (V) at 3 cm above the umbilicus, umbilicus level, and 3 cm below the umbilicus were obtained by high-frequency ultrasound and SWE. Postpartum women were divided into the DRA group and the control group with inter-rectus distance > 2 cm as diagnosis criterion of DRA. The differences in the ultrasound parameters between the two groups were compared. The correlation between the ultrasonic parameters and DRA was analyzed by binary Logistic regression. Receiving operating characteristic （ROC） curve was drawn to analyze the effectiveness of each parameter in the diagnosis of DRA. Results The mean thickness, E and V of rectus abdominis in the DRA group were 7.30±0.67mm,10.85(9.67,12.13)kPa, and 1.85 (1.73,1.97) m/s, respectively. The mean thickness, E, and V of rectus abdominis in the control group were 7.99±0.56 mm, 13.20 (12.23,14.04) kPa, 2.07 (1.97,2.13) m/s. There were statistically significant differences between the two groups (all P < 0.01). Binary Logistic regression analysis showed that lower thickness, E, and V in the rectus abdominis were independent related factors of DRA. ROC curve analysis showed that when E was 12.05 kPa as the cut-off value, the area under the curve for the diagnosis of DRA was 0.852 (95% confidence interval: 0.803-0.902, P < 0.001). Conclusions The stiffness of the rectus abdominis can be quantitatively evaluated via SWE. Lower stiffness and thickness of rectus abdominis are independent risk factors for DRA, and the stiffness of rectus abdominis is more closely related to DRA.