Abstract: Two rice cultivars "CK46" and "Dular" were grown in phytotron experiment treated by 0.0 and 13.0 kJ m -2 day -1 (stimulating 20% ozone depletion) of biologically effective ultraviolet-B (UV-BBE) for four weeks to study the effect of supplemental UV-B radiation on IAA and ABA content in the leaves of rice. The results showed that IAA contents in the leaves of "CK46" and "Dular" were reduced with time course of UV-B radiation. On the contrary,ABA contents in the leaves of both cultivar were dramatically increased when treated by UV-B radiation.