Abstract: The close relationship between the content of chemical element in living things and their environment could be found.The rings of trees in different content of chemical elements which showed the character of their environment at that time.The annual change of content in tree ring spontaneously reflects features of its environment.The late,of course,is influencedby human activity. This paper shows that the content of chemical elements in tree ring is gradually change as well as reflects the corresponding changes with its environment. Using model ln C_{tree ring}=K ln C_soil, we estimated the coefficient K by experements,The result from calculation shows that tha same kind of trees nearly has the same constant K, although they grow in different places We also use this model to discuss the problem of background value of element in different places.