When an elderly person suddenly falls into a coma, he or she should first understand the concept of coma and determine whether the patient is really in a coma. Coma means that the patient loses subjective consciousness, no stimulus can wake the patient, and the patient does not have any voluntary body movement, any speech or eye contact. In elderly people, because of the age problem, the common causes of coma are mainly considered to be cardiovascular disease, hypoglycemic reaction and various types of shock, etc. Attention should be paid to differentiation. Coma caused by cardiovascular disease often has a history of atherosclerosis, with acute onset, and is often preceded by panic discomfort, precordial pain and discomfort, dizziness, uncontrolled movement of the lateral limbs, slurred speech, limb twitching and nausea and vomiting. Coma caused by hypoglycemia is common in patients with diabetes mellitus and can be caused by improper diet or overdose of hypoglycemic drugs, often preceded by weakness, fatigue, sweating and stroke, leading to coma in severe cases. There are many clinical causes of coma in the elderly, and the causes should be actively analyzed further based on the patient’s form of onset, characteristics, clinical symptoms, signs, and the results of various ancillary examinations.