At the end of 2019, outbreak of coronavirus disease 2019(COVID-19) occurred in Wuhan, Hubei Province, and spread rapidly all over the country. The sixth edition of Diagnosis and treatment plan of COVID-19 issued by National Health Commission of the People's Republic of China pointed out that 2019-nCoV may be spread due to the exposure to high concentration of aerosol in a relatively closed environment for a long time, which trigger the public to fear that air conditioning system may cause virus cross diffusion. There are many kinds of air conditioning systems on the market, with different brands and different air treatment methods. This paper sorts out the main types and applicable characteristics of air conditioners used in indoor places, and reclassifies them according to the location and burden range of air conditioning terminal equipment, so as to guide clients and the general public to use air conditioner correctly, eliminate their panic.