Abstract: The drought tolerance of four ornamental Ipomoea batatas （L.） Lam cultivars were evaluated according to the changes of morphological， physiological and biochemical parameters under drought stress. The results showed that， with the drought stress degree increasing， the increments of main vine length， leaf thickness， leaf relative water content and chlorophyll content in the four cultivars all showed a downward trend; the relative electric conductivity， MDA content， soluble sugar content and free proline content showed an increase trend; while the SOD activity， POD activity， CAT activity and soluble protein content increased initially and decreased later. Based on classification of the drought indices through principal component analysis， drought resistance of the four ornamental sweetpotato cultivars were evaluated with subordinate function method and weights. Cultivars with drought resistance from high to low were Qiubite， Ziguiren， Jincancan， Bianerhong.

Key words: ornamental sweetpotato, drought resistance, principal component analysis