Abstract: Effects of enhanced ultraviolet-B radiation on soluble protein and nucleic acid in two rice cultivars(Oryza sati L．)under pot condition were investigated The results show that enhanced ultraviolet-B radiation decreases the biomass．the contents of soluble protein and nucleic acid in rice．With the UV-B radiation increasing．the activities of proteinase and RNase and the content Of tota1 free amino acids increase．while the activity Of NRase decreases．