Abstract: Stratospheric ozone depletion increases solar UV-B radiation (280~320 nm) reaching the earth surface, significantly affecting secondary metabolism in plants. The relationship between secondary metabolite and anti-ultraviolet radiation, insect inhibition, fungal infection prevention and herbivore feeding, litter decomposition and allelopathy is a complicated phenomenon. This relationship affects species composition, inter-species relationship, biodiversity and productivity change, material circulation, geochemical cycle, energy flow isokinetic and ecological balance of the eco-system. The effect of enhanced UV-B radiation on phytocoenosis and ecological systems are summarized in the study, the specific emphasis is played on the ecological significance of enhanced UV-B radiation on secondary metabolism. Furthermore, the study establishes the trend of future research and development in managing UV-B radiation emission.