Abstract： Objective　To establish the normal growth velocity of fetal liver length and compare them with those of intrauterine growth retardation, pregnant diabetes and maternal-fetal blood types imcopatible. Method　Three hundred and five normal pregnant women and 24, 10, 16 pathological pregnant women of intrauterine growth retardation (IUGR), gestational diabetes and maternal-fetal blood types incompatible respectively had ultrasonographic measurement of fetal liver length at 18 to 42 weeks′ gestation. Results　Normal fetal liver length has a linear relation to gestational age, and showed a significantly rapid increase after 28th week with a growth rate of 1.76 mm per week, and 1.00 mm per week before 28th week (P<0.05). The growth rate of IUGR group before and after therapy were 1.19 mm and 1.23 mm per week, significantly lower than those of normal group (P<0.05). The growth rate of pregnant diabetes group before and after therapy were 1.63 mm and 1.63 mm per week, no statistical significance with normal group (P>0.05). The growth rate of maternal-fetal blood types incompatible group before therapy was 1.98 mm, showed no difference with normal group (P>0.05), but after therapy, the growth rate of fetal liver was 1.38 mm per week, significantly lower than normal group (P<0.05). Conclusion　Dynamic measurement of fetal liver length can help us to understand whether the fetus grow well in uterus and whether the treatments are effective.