Objective:To determine the dosage,method and effectiveness of using magnesium sulfate for treating the intractable epilepsy.Methods:72 cases were allocated to treatment group and 36 to control group. For those in the treatment group,either 10 mL of 25% MgSO4 was administered by intravenous drip or 10 mL of 16.5% MgSO4 by oral intake once per day,in addition to the use of the commonly used antiepilepsy drugs. For those in the control group,the commonly used antiepilepsy drugs such as tegretol,sodium phenytoin,luminal or γ-Aminobutyric Acid were employed.Results:The improvement rate in the treatment group was 87.50%,higher than that (44.44%) in the control group (P＜0.01).Conclusion:Using magnesium sulfate in conjunction with the antiepilepsy drugs is a simple yet effective regime for the treatment of the intractable epilepsy.