Abstract: The paper discussed the naming， characteristic， focus， transmission， diagnosis and treatment of COVID-19 based on Treatise on Warm Pestilence. It was suggested that the data related to COVID-19 could be collected to disclose its transmission process in terms of pathogenic characteristic， further explore its diagnosis and treatment modes with regard to the interaction of evil qi and healthy qi， and elaborate the modern significance of latent pathogen and pleurodiaphragmatic interspace (membrane-source) based on the research results in modern medicine and the theory of latent pathogen in the pleurodiaphragmatic interspace. The academic insight of doctrine of epidemic febrile disease in traditional Chinese medicine (TCM) has been further developed and improved through the study on Treatise on Warm Pestilence， epidemiologic analysis， clinical manifestation， laboratory inspection， along with TCM diagnosis and treatment.