The filtration efficiency of medical protective masks decreases over time, so the masks have a certain service life, but there is no definitive conclusion on the optimal time to wear a medical protective mask. Since masks are scarce during pneumonia epidemics of novel coronavirus infections, they can be used for a longer period of time if they are stored and used effectively. Wash your hands before wearing a medical protective mask according to the protocol and avoid touching the inside of the mask when wearing it. The mask should be replaced immediately in case of contamination, moisture, breakage, etc., and the use time should be shortened in high-risk environments.