Magnesium sulfate is an anticonvulsant, commonly used in clinical practice for hypertension in pregnant women, it can help to relieve spasms in patients with blood pressure during pregnancy, it can treat pre-eclampsia and eclampsia, it can also be used for fetal cerebral neuroprotection during preterm birth. Magnesium sulfate plays a major therapeutic role in the anticonvulsant process is magnesium ion, magnesium ion can inhibit the activity of the central nervous system, can inhibit the release of neurotransmitters in the motor neuromuscular junction, can block the conduction of the neuromuscular junction, thus reducing or relieving the contraction of the muscle. There is also a certain diastolic effect on vascular smooth muscle, so that the spasm of peripheral vascular dilatation, so as to reduce blood pressure, has a better preventive and therapeutic effect on eclampsia, and also has a certain inhibitory effect on the contraction of uterine smooth muscle, so it can be used to treat preterm labor. Magnesium sulfate injection in the use of need to pay attention to, for some patients contraindicated, if there is heart block, myocardial injury patients, magnesium sulfate is not recommended, if the patient has serious renal insufficiency, also can not use magnesium sulfate. The use of this drug is also prohibited for patients with bleeding in the intestine and other pregnant women with acute abdomen. In short, magnesium sulfate must be used in hospital.