Abstract: This paper is about the influences of enhanced UV\|B radiation in simulation and drought stress on the protective enzymes and protective substances of Fagopyrum dibotrys， and so as to provide a theoretical basis for the cultivation for F. dibotrys. We took experiments of potted plants， we mensurated the SOD activity， POD activity， total flavonoids contents， free proline contents and soluble protein contents of F. dibotrys under different drought stress and UV\|B radiations. The results showed enhanced UV\|B radiation can increase SOD activity， total flavonoids contents and free proline contents of F. dibotrys under adequate water condition. In the early and late stages of the treatment， POD activity of F. dibotrys was increased by enhanced UV-B radiation. In the early and late stages of the treatment， soluble protein contents of F. dibotrys was increased by enhanced UV-B radiation. In conditions of drought stress， enhanced UV-B radiation increased SOD activity of F. dibotrys in the middle stage of the treatment while decreased it in the early and late stages of the treatment. In the late stage of the treatment， enhanced UV-B radiation increased POD activity， free proline contents and soluble pro-n contents of F. dibotrys. In conditions of drought stress， F. dibotrys reduced the adverse effects by regulating protective enzyme system and protective substances， the enhanced UV-B radiation improved the resistance of F. dibotrys to drought stress to some extent.

Key words: Fagopyrum dibotrys, drought stress, enhanced UV-B radiation, enzyme system, protective substances