Zhang Zhongjing′s quantitative thinking mode in syndrome differentiation was explored through inductive analysis and classification on Treatise on Febrile Diseases in the perspective that zang-fu organs interior-exterior relationship for disease location，cold and heat，deficiency and excess for disease nature，symptom and sign for disease trend，pulse and syndrome for prognosis.Thereafter，his intention for quantitative method and standardization for syndrome differentiation was understood for better clinical practice.