A number of dictating resins have been synthesized for extracting uranium from scawatcr. The feasibilities of extracting uranium directly from seawater by synthesizing chelating resins have been investigated by studying three factors: (1) the chelating ability of the resins for uranyl ion; (2) the competitive complex of calcium, magnesium and other cations with uranyl ion; (3) the competitive complex of carbonate ion with uranyl ion. It is suggested that the competitive complex of carbonate ion with uranyl ion should be the most important factor.