Abstract: The adsorptive behavior of polymer of methyl aldehyde of dibenzo-18-crown -6 (PDB-18C6) in hydrochloric acid medium is studied and it is shown that the adsorption of T1(Ⅰ) ,Au(Ⅲ) ,and Cu(Ⅱ) depends on the particle size of the crown ether resins, hydrochloric acid concentration and amount of the crown ether resins used.The difference in the adsorption behavior of different particle sizes of crown ether resins may be used for separating T1(Ⅰ) ;Au(Ⅲ) ,and Cu(Ⅱ) ions, The best eluant of T1(Ⅰ) and Au(Ⅲ) is 0.4mol/l perchloric acid and 2-ethoxy-ethanol.The recovery for T1(Ⅰ) is 82-98.9%. The gold target is bombarded in a 1.2 m cyclotron with 25-27 MeV a-particle with a cumulative beam intensities of 27μA·h, and 199T1 is separated from the gold target with PDB-18C6. γ-spectrometry has shown that the T1 obtained is 193T1 of high purity containing only about 0.50%200T1.