It is believed that qi is the material basis of the unity of nature and man

and qi transformation is the theoretical basis for the unity of nature and man.From the perspectives of five evolutive phases and six climatic factors

correspondence between human body and natural environment

the attributes of six qi

qi transformation in manifestations and root causes

spiritual mechanism and qi origination

acupoints of root meridians

nature and flavor of herbs

five zang organs and six fu organs

meridians and acupoints

association of zang-qi with the four seasons

qi movement in the middle

image forms outside

the constitution of body and disease tends

this paper explained the theoretical basis and main carrier of the theory of unity of nature and man in traditional Chinese medicine.It is believed that qi transformation theory is the core of the theory of five evolutive phases and six climatic factors

which influences and promotes the emergence and development of the theory of six meridians qi transformation in Treatise on Cold Pathogenic Diseases（《伤寒论》）.