Abstract： This paper introduces Prof. XU Jiadong's understanding of ZHANG Zhongjing's thought of “wind stroke syndrome in the six stages of diseases”. Prof. XU believes that ZHANG's thought of wind stroke syndrome existing in the six stages of diseases reflects the academic characteristics of classical prescription system in ZHANG’ s eyes， which is to differentiate the exterior and interior syndrome first and pay more attention to the exterior syndrome. ZHANG attached great importance to the pathogenic rule of exterior pathogen invading from the shallow to the deep and from the exterior to the interior. In the process of the rehabilitation of disease， it is also necessary to pay attention to the rule of rehabilitation of recovering from the deep to the shallow and from the interior to the exterior. Thus， Prof. XU Jiadong puts forward the academic viewpoint of “interior pathogens coming out and then yin disease turning into yang disease”，which reveals the rule of rehabilitation of the six stages of diseases，and provides an idea and method for clinical syndrome differentiation.