Abstract: Objective：To construct a normal value range for the internal diameter of fetal colon in late pregnant term . Methods：193 cases of healthy pregnant women with normal singleton pregnacies at 36～40 weeks+3 days of gestation. Measured the maximum internal diameter of fetal colon. Results：The normal mean and the 95% prediction limits were defined. Conclusions：The present data provide a normal value range of fetal colon in different gestational age of late pregnant term，may evaluate the development of fetal colon and serve as a reference values in the detection of anomalies of the fetal bowel by ultrasound.

Key words: Ultrasonography, Fetus, Colon, Pregnancy, Reference values