Abstract: By combing the mechanism of retrograde transmission of damp-heat epidemic to the pericardium, it is believed that the retrograde transmission of damp-heat epidemic to the pericardium is the transmission trend of damp-heat turbid epidemic evil from the lung wei or lung to the pericardium, and the turbid evil harming the clear is an important pathological mechanism leading to the retrograde transmission of epidemic evil. Clinical treatment should be based on the theory of turbid evil harming the clear, and the lung qi should be disseminated to promote yang first to cut off the retrograde transmission of epidemic evil; if retrograde transmission occurs, phlegm and turbidity should be removed to promote yang, and be careful to prevent the separation of yin and yang.