Abstract:The effects of ultraviolet B (UV-B) radiation on the phenylpropanoid compounds in common buckwheat (Fagopyrum esculentum Moench) herb were studied by HPLC method. The results showed that not only the contents of flavonoid compounds, such as rutin and quercetin, were significantly increased, but also those of phenolic compounds, eg. ferulic acid and P-coumaric acid, were markedly enhanced. The enhancements of two kinds of compounds provided important protection against UV-B injury in buckwheat herbs.