Objective To investigate the effect of expectant management on the maternal and/or infant out-comes of early onset severe preeclamp sia in different gestafional weeks. Methods A retrospective study was carried out on 158 patients with early onset severe preeclampsia. They were divided into three groups according to their onset gestation ago:group A( <28weeks,n=28) ,group B(≥28、<32weeks,n=51) and group C(≥32、< 34weeks,n =79). Results The rates of complications declined along with the postponement of the onset gestation age, but there was no statistical significant difference among these three groups. The neonatal asphyxia rate and perinatal infant mor-tality of these three groups declined along with the postponement of gestation age, and there were statistical significant differences among these three groups ( P<0.05 ). Expectant treatment time of group B was significantly longer than that of the other two groups ( P<0.05 ), and cesarean section was a main method of pregnancy termination for the groups B and C. Conclusion The smaller the gestational ages in the early onset severe preeelampsia,the higher the maternal and/ or infant complication rates, neonatal morbidity and mortality.