Abstract: Based on the contents of "Pestilence Occurring after Three Years" in Su Wen Yi Pian, using the theory of five evolutive phases and six climatic factors and five elements, it analyzes the pathogenesis and characteristics of five evolutive phases and six climatic factors of COVID-19. It is concluded that its development history is roughly rooted in the failure of defense between celestial manager qi and telluric qi in Dingyou Year, with the Pestilence of Wood after three years. Then, it is occurring at the end of six climatic factors in Jihai Year, and it is growing at the beginning of six climatic factors in Gengzi Year, weakening in the second six climatic factors and dying in the third six climatic factors. It is concluded that its main characteristic of five evolutive phases and six climatic factors is the excess of Metal, the stagnation of Wood and the recovery of Fire, and the pathogenesis of different solar terms are in a dynamic change, suggesting that the prescription selection of Chinese materia medica and acupuncture should be changed with time, and that prevention should be carried out as early as possible. The five evolutive phases and six climatic factors in Dingyou Year is characterized by the lack of Wood, the excess of Metal and the recovery of Fire. If celestial manager qi in the earth fail to defend in Dingyou Year, the Pestilence of Wood is occurring after three years, at the beginning of Gengzi Year or the end of Jihai Year. The five evolutive phases and six climatic factors in Gengzi Year is characterized by the excess of Metal, the stagnation of Wood and the recovery of Fire. The consequence of mutual fight between Metal and Fire is that Metal is superior to Wood and Earth is weakened due to Wood. When Fire is coming to help Wood and overpower Metal, the Pestilence of Wood would stop. The characteristics of five evolutive phases and six climatic factors closely linked to the Pestilence of Wood can guide the prevention and treatment of TCM. Pay attention to the Theory of five evolutive phases and six climatic factors and strengthen the prediction and prevention of epidemics.