Effect of UV-B radiation on ingesting and nutritional selecting behavior of the roifer Brachionus urceus on 5 species of micro-algae were studied under controlled laboratory conditions. Results showed that enhanced UV-B radiation significantly inhibited ingesting of the rotifer B. urceus when it was fed with 5 species of micro-algae (p<0.05). The ingesting selectivity rate varied with the UV-B radiation enhancement when it was fed with 5 species micro-algal mixture. Results indicated that the enhanced UV-B radiation could affect ingesting and nutritional selectivity of B. urceus. Effect of UV-B radiation on ingesting and nutritional selecting behavior of the roifer Brachionus urceus on 5 species of micro-algae were studied under controlled laboratory conditions. Results showed that enhanced UV-B radiation significantly inhibited ingesting of the rotifer B. urceus when it The ingesting selectivity rate varied with the UV-B radiation enhancement when it was fed with 5 species micro-alga mixture. Results indicated that the enhanced UV-B radiation could affect ingesting and nutritional selectivity of B. urceus.