Primary prevention of stroke is the etiologic treatment aimed at reducing the incidence of stroke through intervention of high-risk causative factors. The first step in primary prevention is to understand the risk factors that cause stroke. Epidemiological surveys have shown that the causes of stroke can be divided into two categories: those that cannot be intervened, such as age, gender, family history, and race; and those that can be intervened, such as hypertension, hypotension, diabetes, hyperlipidemia, obesity, coronary artery disease, atrial fibrillation, cerebrovascular stenosis, smoking, alcohol consumption, and low physical activity. Primary prevention of stroke is to control its onset at the source. Community physicians should have a good understanding of the risk factors for stroke and the prevention and control measures to prevent the onset of stroke by intervening in the risk factors while providing health education to patients with these risk factors. The level of awareness of stroke prevention and control among community doctors directly affects the success or failure of stroke prevention and control, therefore, primary prevention of stroke is focused on the community. Community physicians should master the diagnosis of stroke and the time window for thrombolytic treatment; once a stroke occurs, the receiving physician should send the patient to a hospital with a stroke unit for thrombolytic treatment in the first instance. The time of onset, symptoms, blood pressure, heart rate, opening of intravenous tract, saline maintenance, and no glucose infusion without special circumstances should be recorded in detail during the process of receiving and transferring the patient. The time window for thrombolysis is 4.5 hours. 4.5 hours is very important to the patient, and time is life. Community physicians and 120 physicians should keep the time window in mind to win the best treatment time for the patient and minimize the disability and mortality rate.