Based on the transmission characteristics of Corona Virus Disease 2019（COVID-19），this article analyzes the health risks caused by improper operation and management of air conditioning ventilation systems，such as fresh air volume，fresh air outlets，return air，U-shaped pipes and humidification. It is proposed that during the COVID-19 epidemic，fresh air should be increased，the fresh air outlet should be kept clean，the return air should be reduced as much as possible，and the humidification function should be turned off to avoid the risk of transmission of COVID-19 due to improper use of the air conditioning system.

Corona Virus Disease 2019, Air conditioning and ventilation system；Sanitation