KN90 masks are preventable against the new coronavirus. Current medical surgical masks and KN90 and N95 masks are all preventive. There is no need to wear N95 masks if there is no contact with infected patients and non-health care workers. Novel coronavirus can be transmitted through droplets, and contact and droplets splashed into the eyes can also be transmitted through the conjunctiva. Therefore, the main thing is to reduce going out in general, try not to go to crowded and crowded places without necessary things, and keep a distance of more than 1 meter from other people’s communication.