Sudden decrease of blood pressure needs to check blood routine, cardiac ultrasound, chest CT, gastroscopy and other tests. Sudden decrease of blood pressure should be excluded whether it is caused by antihypertensive drugs, and then consider whether there is hemorrhage, shock, aortic coarctation and other diseases, and improve the relevant examination according to the disease. 1. Blood routine: blood routine can indicate acute and chronic blood loss in hemorrhage caused by various reasons, and according to the hemoglobin level and the patient’s symptoms, we should consider whether blood transfusion is needed. 2. Cardiac ultrasound: some patients have heart disease, cardiogenic shock and lower blood pressure can occur, perfect cardiac ultrasound and electrocardiogram and other tests can clarify whether there is heart disease. 3. Chest CT: patients with aortic dissection may have a sudden drop in blood pressure, so it is necessary to improve chest CT examination, and improve angiography if possible. 4. Gastroscopy: peptic ulcer with bleeding or gastric cancer with bleeding, large amount of bleeding, blood pressure drop, pallor, weakness, gastroscopy is needed to clarify whether there are such diseases. There are many reasons for the sudden drop of blood pressure, so consult the doctor in time to find out the condition and cooperate with the doctor for diagnosis and treatment.