Intravenous thrombolysis is a common treatment for thrombosis, and it has two forms of treatment, the first is systemic intravenous thrombolysis, and the second is catheter-contact thrombolysis, which means that the catheter is placed by interventional methods and then thrombolysis is given. There are three main complications of thrombolysis, the first is bleeding, the second is allergy, and the third is reperfusion injury. Hemorrhage is the main complication, which can be manifested as gastrointestinal bleeding, cerebral bleeding, urinary bleeding, etc. If bleeding occurs, thrombolysis should be stopped immediately. Allergic reaction, very few patients will have allergic reaction to urokinase or streptokinase, with chills, asthma, rash, and in severe cases, anaphylaxis may occur. Reperfusion injury is also a common complication of thrombolysis, for example, thrombolysis in patients with long infarction can cause myocardial weakness or even death due to heart rupture and bleeding. Therefore, the changes of tissues after thrombolysis should be closely observed.