The descriptions about the traveling routes of meridians in ancient Chinese literatures directly reflect the understanding and recognition of the ancient Chinese physicians on "meridians" concept at that time.Therefore

the changes of meridian traveling routes in different ancient Chinese periods certainly reflect the changed connotations of meridians.Beginning from va-riations of the starting and ending points

direction and traveling routes of book Ling Shu Jing(Miraculous Pivot)and the "eleven meridians" in the Silk Book

the authors of the present article hold that the main factors influencing the variation of meridian traveling pathways are 1)development of the pulse diagnosis

2)ancient Yin-Yang and math ideology

3)ancient surface anatomy knowledge

and 4)formation of the concepts of Qi

Xue(blood)

and Ying-Wei circulation.The authors also analyze the significant evolution of meridian concept and connotation from the "eleven meridians" to the "twelve regular meridians".