This paper introduces Professor JIANG Liangduo’s understanding on etiology

pathogenesis and treatment methods of coronavirus disease（COVID-19） in traditional Chinese medicine. It is proposed that "qi failing to control fluid"is the key pathogenesis. Qi failing to control fluid causes yin fluid in lung transforming into phlegmdampness

which presents the danger of internal blockade of phlegm-dampness and qi and yin deserting outwards. The disease is located in lung. The key to treatment is to protect major-qi in the chest and emphasize early application of medicines that invigorate qi. Dampness pathogen transforms into dryness with upper attack of toxin

and it can not be treated as disease of dampness-heat in middle jiao. Purgative method should be used with caution

and xuefen medicines should not be applied too early. Take care of heart and lung yang

and use pungent and warm heavy formula with caution. If there is no danger of internal blockade and external collapse

dampness-heat can be eliminated through purgation and diuresis to work slowly.