Wearing a mask belongs to the protection of susceptible people. People with low body immunity or recurrent colds can be prevented from getting sick by wearing masks properly. Most respiratory diseases are contracted through coughing and droplet saliva transmission, such as colds, flu, and new forms of coronary pneumonia. Susceptible people, especially those with low immunity, can effectively block the infection and spread of viruses by wearing masks correctly, thus preventing themselves from contracting diseases. Medical surgical masks or N95 masks can be used, and attention should be paid to the way and method of wearing. In addition to wearing masks, susceptible people can prevent the occurrence of diseases through appropriate sports and exercise, diligent hand washing, diligent ventilation, less gathering, balanced nutrition and so on. Usually susceptible people should try to avoid contact with sick patients, patients infected with the disease need to go to a regular hospital, reasonable treatment.