〔Abstract〕 Objective To explore the relationship between expectant treatment and perinatal outcome of early onset severe preeclampsia. Methods 244 cases of early onset severe preeclampsia with singleton were selected as the study object. After admission, the patients were divided into two groups: immediate termination group(89 cases) and expectant treatment group(155 cases). The expectant treatment group was divided into four groups according to gestational weeks: group QA(<28 weeks, 15 cases), group QB(28-30 weeks, 36 cases), group QC(30+1-32 weeks, 47 cases), group QD(32+1-34 weeks, 57 cases). Results ① Compared with immediate termination group, the birth weight increased, HELLP syndrome、placental abruption、ICU occupancy rate and neonatal mortality rate decreased in expectant treatment group(P<0.05). ② The rate of cesarean section in group QC and group QD was higher than that in group QA(P=0.002). ③ The birth weight increased with the prolong of gesta-tion in group QA, QB, QC and QD; the 5-minute severe asphyxia rate of group QB、QC and QD was lower than that of group QA,and group QD was lower than group QB; the stillbirth of group QB、QC and QD was lower than that of group QA,group QD was lower than group QB; the neonatal mortality rate of group QD was lower than that of group QA and QB; the survival rate of newborns in group QB、QC and QD was higher than that of group QA,group QD was higher than group QB,the difference was statistically significant( P<0. 05). Conclusion(1) Patients should be strictly selected,and expectant treatment should not be given blindly;(2) For patients with stable condition,expectant treatment should be carried out under strict supervision to improve neonatal outcome. However,whether expectant treatment should be given to patients under 28 weeks needs further study.