Zangshi irrigation area is the notorious heavy pollution area by Cd in China. In this paper, different kinds of ecocycle model are revealed i.e., how Cd was transformed from pollution sources into irrigation water, agroeccosystem and human body. It is stated that there is an active cycle of Cd in natural envilbn-ment, specified irrigation system, cultivated crops and food composition. Human health is seriously affected in Zhangshi irrigation area.