Abstract: The influence of enhanced UV-B radiation on agricultural ecosystem and crop output is an area widespreadly attracting researchers.The paper introduced the characteristics and accumulation of flavonoid in plants whose synthesis is stirred up under UV-B radiation. Ecological and physiological effects and mechanism of flavonoid resistance to UV-B radiation are also analyzed.The relationship between flavonoid and other anti-UV-B radiation machanism are discussed from several angles laying the basis for future studies.