Abstract: The adsorption efficiencies of the algae to uranium ion were determined at various pH, uranium ion concentrations, adsorption temperatures and the species of coexisted metal ions, and the effect of coexisted metal ion on the adsorption efficiency was researched. The experimental results at pH=5-8 are as follows:1) the adsorption capacity is a constant to be about 1.40 μg/g for the Yantai red alga and the sea spinach, and is changeable in the range of 1.03-2.23 μg/g with pH for the sea edible fungus; 2) for the algae the adsorption efficiency and adsorption capacity are related to uranium ion concentration, and the maximum adsorption efficiency and capacity is 95.8％ and 65.4 μg/g, respectively; 3) the adsorption process for 24 h is not dependent on the temperature; 4) the effect of the species of coexisted metal ions on the adsorption capacity of uranium ion is various with the time during adsorption process.