Abstract: The radioactive Ba isotopes are produced in the interaction of 60 MeV/u 18 O with 232 Th. Ba is separated from thorium and complex reaction product mixture by BaCl 2 precipitation and purified. 133 Ba is used as the tracer to determine chemical yield of Ba. The Ba fraction is measured by off line gamma ray spectroscopy. The formation cross sections of the individual Ba isotope is calculated from the intensities of gamma ray peaks of each Ba isotope as well as relative nuclear data. The results show the n deficient Ba isotopes still have higher formation cross sections under the conditions of intermediate energy projectile and thick targets.