Wearing a mask can protect you from catching the flu, but it has a limited effect. Influenza is an infectious disease of the respiratory system caused by the influenza virus. The source of influenza is influenza patients. The way of transmission for droplet transmission, influenza patients sneezing, coughing droplets will be scattered in the air, infectious. Masks on the one hand can block the influenza patients spray droplets, reduce the speed of droplet spray and the amount of spray droplets, thus preventing the influenza patients through the droplet infection of others; on the other hand, masks into the nasal cavity of the air can be effectively filtered to block the virus-containing droplet nuclei into the human body, thus playing a protective role for the wearer of the mask. Wearing a mask can effectively prevent influenza, but can not filter 100% of the virus, the higher the level of protection of the mask the better. Warm reminder: influenza epidemic season, the need to reduce access to public places, standardize the wearing of masks, enhance immunity to prevent infection with influenza virus; such as influenza, the need for timely hospital diagnosis and treatment.