Gestational hypertension syndrome (hypertension) is a common but serious condition that affects the safety of mother and child. The maternal mortality rate due to hypertension can be significantly reduced by improving prenatal screening and management. A small number of patients with severe hyperemesis gravidarum whose blood pressure is very high and cannot be controlled by the above-mentioned medications may be treated with this drug under close observation. Sodium nitroprusside mainly acts on vascular smooth muscle, dilates arterioles and veins, reduces peripheral vascular resistance and cardiac end-diastolic pressure, resulting in a rapid decrease in blood pressure, improvement of cardiac function and increase in cardiac output. The following is an introduction of sodium nitroprusside precautions: 1. The antihypertensive effect is very fast, usually after 2 to 3 minutes of drip is effective, so the blood pressure should be measured once every 5 minutes, and after adjusting the drip rate until the antihypertensive effect is satisfactory, the blood pressure can be measured once every 10 minutes. Diastolic blood pressure should be maintained at 12~13kPa (90~100mmHg), not too low. 2.Nitroprusside is sensitive to light and becomes blue after seeing light, so it should be wrapped with black paper or tinfoil to cover the injection bottle. 3, because the drug quickly into the fetal circulation, so when the patient’s blood pressure drops and symptoms improve, the delivery should end as soon as possible, in favor of the safety of mother and child. 4.The direct metabolites of sodium nitroprusside can be cyanide, and should be used with caution in people with serious impairment of liver function.