The present study is to investigate the differences of Hg,Cr,Pb,Cd and Zn contents among water area ecology stystems of the three gorges Reservoir from water,dirt mud of the bottom and benthic fishes.The result show that content distribution of trace elements is:dirt mud of the bottom>benthic fishes>water;content distribution of trace elements in benthic fishes is:viscera>muscle>bone.The distribution factor of dirt mud of the bottom versus water,adsorption coefficient of benthic fishes versus dirt mud of the bottom and enrich coefficient of benthic fishes versus water is constant value in three Gorges Reservoir.Mercury is harm element to human in food chain.Besides,transform model of food chain in trace element are studied.