Abstract： Objective To discuss the serum endoglin expression in severe pre-eclampsia and eclampsia women and their relationships. Methods Forty-two severe pre-eclamptic patients and 4 eclamptic patients in Peking University First Hospital from Dec. 2005 to Dec. 2007 were enrolled in the study group, with the mean gestational week of 35 ± 4, the mean age of 29.3 ± 5.7 and the mean BMI (30.1 ± 4.1 ) kg/ m2. This group included 25 cases of early onset pre-eclampsia, 21 cases of late onset pre-eclampsia, 8 cases of fetal growth restriction and 5 cases of HELLP syndrome. The control group included 29 cases of normal pregnant women during the same period, with the mean gestational week of 33±4, the mean age of 30.7± 3.4 and the mean BMI(27.2±2. 2) kg/m2. Peripheral serum endoglin was determined by ELISA in these two groups. Results (1)There is positive correlation between serum soluble endoglin level and the gestational weeks during 27 to 37 gestational weeks in the control group (r=0.79, P<0.05), but there is no distinct relationship in the study group (r=0.31, P>0.05). (2) Serum endoglin level of severe pre-eclampsia group was higher than the normal group [(14.2±5.6)μg/L vs. ( 10.9 ± 4.2 ) μg/L, P<0.05]. (3) Serum endoglin level of early onset group did not differ from late onset group [(14.3±5.7)μg/L vs. (13.6±5.0)μg/L, P >0.05]. (4) No difference of serum endoglin between HELLP group and non-HELLP group was found [(10.1±2.9) μg/L vs. ( 14.4±5.4) μg/L, P>0.05 ]. (5) Serum endoglin level of FGR sub group was higher than non-FGR sub group [(17.3±6.1) μg/L vs. (13.0±4.8) μg/L, P < 0.05] in the stady group. Conclusion The elevated peripheral serum endoglin level may contributes to the pathogenesis of severe pre-eclampsia and FGR, but not the week of the onset of the disease.