The dynamics of transportation,accumulation,disappearance and distribution of 60Co in a simulated aquatic-terrestrial ecosystem was studied by isotope-tracer technique.In the aquatic system,60Co was transported and transformed via depositing,coupling with ions and adsorption.The absorption resulted in the redistribution and accumulation of 60Co in each compartment of the system.Specific activities of 60Co in water started sharply and gently decreased.The sediment accumulated a large amount of 60Co by adsorption and ion exchange.The homwort (Ceralophyllum demersum) could also adsorb a large amount of 60Co in a short time,because of its large specific surface area.Fish (Carassius auratus) and snail (Bellamya purificata) had a poor capacity of adsorbing 60Co.The distribution of 60Co in the fish was mainly in the viscera,and the amount of 60Co in the snail flesh was greater than that in the shell.The amount of 60Co in individual compartment in the system was changed with time.The highest specific activity of 60Co in the bean of the terrestrial system remained in the root nodule.