Nitroglycerin takes effect immediately after pumping into the vein and expires in about 5-10 minutes. Nitroglycerin mainly dilates arteriovenous vessels and its strength is positively correlated with the dose. When using nitroglycerin intravenous injection, attention should be paid to avoiding light, and the use time is generally appropriate within 24 hours, too long is prone to nitroglycerin resistance. Nitroglycerin intravenous injection is mainly used for patients with acute myocardial infarction, unstable angina and congestive heart failure, it has the effect of reducing the anterior and posterior loads on the heart, dilating coronary arteries and relieving angina, when using nitroglycerin, attention should be paid to monitoring blood pressure to prevent it from becoming too low.