Abstract: The accumulation of UV-B absorbing materials (measured at the wavelength band of 280~320 nm) induced by UV-B radiation and possible involvement of a protective screening against UV-B radiation were investigated in five constructive species of low subtropical forest in South China. The methanol soluble extracts and alkali-extractable cell wall-bound phendics were significantly higher in needles of Pinus massoniana under supplementary UV-B radiation than under normal level of sunlight. These compounds were also enhanced in leaves of Castanopsis hystrix and Cryptocarya chinensis, implying that the supplementary UV-B radiation stimulated the synthesis of UV-B radiation absorbing materials, forming a functional protecting screen against UV-B radiation. However, Schima superba and Castanopsi fissa that contained relatively high alkali-extractable cell wall-bound phendics under natural sunlight exhibited a decrease in content of these compounds when exposed to supplementary UV-B radiation, suggesting that under supplementary UV-B radiation the cell wall-phendics in epidermal cell layers might be transformed into soluble compounds in vacuoles where there were lower contents of methanol soluble pigment. This fact assumes that a strategy for protection of photosynthetic apparatus hidden in mesophyll tissue was evolved. Chlorophyll a+b content (μg g-1) was not affected in the needles of P. massoniana and a decrease of 10.7% to 16.8% (mg m-1) occurred in the leaves of the other examined broad-leaved tree species under exposure of supplementary UV-B radiation. Response of carotenoids to supplementary UV-B radiation was variable: The decreased level of carotenoid was observed in C. hystrix and S. superba, and carotenoids were stimulated in P. massoniana, C. chinensis and C. fissa, which might be a functional increase in dissipation of excited energy. The results showed that different acclimation strategies were developed to protect against the increasing UV-B radiation in nature and flavoid screen in the acclimation to UV-B radiation was an important feature of adaptation process in the plants of low subtropical forest. Tab 4, Ref 29