Inherited the syndrome classification of six meridians in the chapter about fever of Basic Questions(Su Wen Re Lun), taken the theory of meridian and collateral as the basis of syndrome differentiation and treatment, the theory of six meridians was enriched and developed in Treatise on Cold Pathogenic Diseases from some aspects including enrichment of syndrome differentiation of six meridians,development of identification of progression and self healing of six meridians,supplement of transmission patterns in six meridians related diseases,enlargement of syndrome and classification of six meridians,improvement of treatment principles and methods in six meridians related diseases, which improved the application value of syndrome differentiation and treatment of six meridians in clinic.