Abstract: The effects of drought stress on growth, physiological and photosynthetic characteristics of Iris milesi and Vinca major var. Variegata grown in pots were studied to understand difference between the two species in respect of drought tolerance ability .The results showed that under drought stress V. major var. Variegata had lower relative growth rate than I. milesi did, with increased content of malondialdehyde（MDA）in the leaf and more decreased root activity. With increasing degree of drought stress superoxide enzyme（SOD）activity of I. milesii had a trend to decrease but SOD of V. major var. Variegata and peroxidase enzyme（POD）of I. milesii increased first and then decreased, with reversed tendency for POD of V. major var. Variegata. Net photosynthetic rate（Pn）and chlorophyll content of both two species increased at the beginning and decreased afterwards, with higher photosynthetic rate for I. milesii. According to the indicators quoted above the two tested species could be considered as plants with more or less strong drought resistance ability, of which I. milesii was higher than that of V. major var. Variegata.

Key words: drought stress, ground cover plants, growth, physiological and photosynthetic characteristics