Aim: The study was to determine whether preeclampsia with superimposed chronic hypertension results in worse maternal and perinatal outcomes than preeclampsia alone. Materials and Methods: A retrospective study involving 850 pregnant women was conducted and divided into two groups: preeclampsia superimposed on chronic hypertension (group A, n= 84) and preeclampsia alone (group B, n= 766). The maternal and fetal outcomes of all subjects were collected and analyzed. Results: There were no significant differences between the two groups in baseline information. However, the systolic and diastolic blood pressures in group A were significantly higher than those in group B (p < 0.05). The average interval between the onset of preeclampsia and the termination of pregnancy was significantly longer in group A as compared to group B. The incidence of serious maternal complications showed no differences between the two groups (p > 0.05). It showed a higher rate of neonatal respiratory distress syndrome and intracranial hemorrhage in group A than in group B (p < 0.05). Conclusions: Women in group A had higher risks of maternal and perinatal outcomes as compared to women in group B.