Whether multi-layer masks can protect against new coronavirus should be analyzed specifically. In general, as long as a qualified medical surgical mask or N95 mask is used in a standardized manner, it can basically protect against new coronavirus. Stacked use of multi-layer masks theoretically does not enhance its protective effect, and will lead to poor breathing and discomfort for the wearer. Multi-layer masks may affect the airtightness of the mask and reduce its protective effect, so it is not recommended to bring multi-layer masks. For example, it is not recommended to wear N95 mask after taking ordinary mask, because it will affect the airtightness of the mask, and it is not possible to take multi-layer ordinary mask. However, sometimes medical staff working in infection wards can wear N95 masks first and then medical surgical masks outside of N95 masks in order to enhance their protective effect. Therefore, it is not recommended to bring multiple layers of masks to protect against viruses in daily life.