Objective Retrospectively analyze the data of 9 cases of eclampsia in hospital is conducted and and the measures of how to avoid and decrease the occurrence of eclampsia were discussed. Methods Nine cases were diagnosed as eclampsia in hospital from 2002 to 2009 and their clinical data were analyzed. The 9 cases were divided into 2 groups. Group A was defined as the cases diagnosed as severe pre-eclampsia before eclampsia attacked and eclampsia attacked in hospital after treatments, and 3 cases met these criteria. Group B was defined as the cases diagnosed as pre-eclampsia or hypertensive disorders complicating pregnancy before eclampsia, and 6 cases met these criteria. The eclampsia in group B attacked after labor. Results ①All cases in group A were treated in hospital with Magnesium sulfate, but none was applied with Magnesium sulfate when eclampsia attacked. The longest interval of Magnesium sulfate was 45 hours and the shortest was 6 hours. Eclampsia before labor happened in 1 case while 2 cases occurred after labor. ② The attack of Eclampsia in group B was all in the active phase. All of them had eclampsia after delivery and none of them were treated with Magnesium sulfate. The blood pressure was normal or mildly increased. The eclampsia didn't attack after effective treatment. Conclusion Magnesium sulfate is the most effective drug to prevent eclampsia. ①The pregnant women with severe pre-eclampsia should be given sufficient Magnesium sulfate before labor and during and after labor. ②For those women with normal and mild increased blood pressure, clinicians should give enough attention to the change of blood pressure and avoid undesirable stimulation, and timely apply with magnesium sulfate.