【Abstract】: Objective: To investigate the difference of fetal anterior abdominal wall thickness between normal pregnant women and gestational diabetes mellitus pregnant women in second and third trimester of pregnancy. Methods: According to the results of 75g oral glucose tolerance test, 32 pregnant women diagnosed with gestational diabetes mellitus were selected as the observation group, and 60 normal pregnant women were selected as control group. Fetal ultrasound was used to measure the biparietal diameter (BPD), femur length (FL), abdominal circumference (AC) and anterior abdomen wall thickness (AAWT) between normal pregnant women and gestational diabetes mellitus pregnant women. And compare the differences between the two groups. Results: There were significant differences in the thickness of the anterior abdominal wall between control group and observational group(3.97±0.64mm vs 3.10±0.27mm, P<0.01). No significant difference was observed in the BPD、FL and AC（P>0.05）. Conclusions: The measurement of fetal anterior abdominal wall thickness, used for evaluating fetal growth during diabetic pregnancies, can be served as one of the indexes for the ultrasound evaluation of gestational diabetes mellitus. It has an important clinical significance and value for the diagnosis of gestational diabetes mellitus.