It is considered that coronavirus disease 2019（COVID-19） in Guangdong was caused by pestilent qi of heat toxin. According to the onset season and the nature of the pathogen

COVID-19 in Guangdong can be attributed to the category of warm-pathogen dominant pestilence

which was called "wind-warmth" or "warm-heat epidemic". Based on the comprehension of etiology and pathogenesis of COVID-19 in Guangdong

the formulation principle of Pneumonia No.1 Formula（肺炎1号方） was analyzed; and the innovation of the therapeutic principles lied in that qi-boosting and yin-nourishing method was integrated when clearing heat and resolving toxins

venting pathogen through clearing and diffusing the lung

and relieving cough and dissolving phlegm. The analysis could provide a reference for using traditional Chinese medicine to treat COVID-19 and other emerging respiratory infectious diseases of sudden onset.