Abstract： The article is to introduce Professor FAN Guanjie's clinical experience in treating exogenous febrile diseases by syndrome differentiation based on variable-stable and sequential thinking. Professor FAN Guanjie believes that it will affect the clinical effect and result in limitations and one-sidedness if it is to adhere to a single syndrome differentiation and treatment system of exogenous febrile diseases. Guided by the variable-stable and sequential thinking， which emphasizes holistic and dynamic perspectives， he advocates analyzing etiology and pathogenesis through syndrome differentiation. He also identifies constraint heat as the core pathogenesis of exogenous febrile diseases. By discerning pathological trends， his therapeutic strategy focuses on unblocking stagnation， guiding treatment according to disease progression，dispelling pathogens while reinforcing healthy qi，which is a concise and effective syndrome differentiation and treatment thinking for the diagnosis and treatment of exogenous febrile diseases.