Abstract: The use of poly-dibenzo-18-crown-6 as a new ion-exchange resin for trace U(Ⅵ) in picric acid medium is described. The adsorption efficiency can be raised by adding a small quantity of ethanol. The PDB-18C6, as compared with DB-18C6, shows a good adsorption action for U(Ⅵ) when the concentration of picric acid as 2×10-2M volumetric ratio of picric acid to ethanol is 3.5 to 1. It is found that the adsorption for U(Ⅵ) is quite different from that of Th, Ti or Fe. In addition, Ti is eluted out with picric acid, and U(Ⅵ) with 0.1 M HC1. The new resin is shown to be valuable for the separation of U(Ⅵ) and Ti.