This paper summarized the therapy of regulating yin and yang in Treatise on Febrile Diseases from 4 aspects, including “Qi deficiency when the evil raised”, “receding its excess and supplementing its deficiency”,“nourish yin when yang excess,and warm yang when yin excess”,“focus on yin and yang to except its balance”. It was put forward that regulating yin and yang is not only supplying deficiency and expelling excess simply depending on patient’s cold-heat and deficiency-excess. The basic reason of imbalance of yin and yang through the surface should be estimated. Treatment should pay attention to flexible regulation of the degree on supporting healthy energy and eliminating evils,and supplying deficiency and expelling excess.