The effects of water stress induced by polyethylene glycol 6000(PEG 6000) on morphological characters and membrane permeability of seedlings were studied using 8 varieties of potatoes. Each of the potato varieties was treated with 0(CK), 5%, 10%, 15%, 20%, 25% and 30% PEG respectively. The results showed that leaf size and number decreased with increasing concentration of PEG. Leaf numbers of all the materials but Xiang Potato 1 were significantly lower than CK when treated with 10% PEG. The elongation of stems was more sensitive to drought stress, which were significantly inhibited by 5% PEG treatment compared to CK and internodes number was susceptible to 10% PEG treatment. The root growth was more sensitive to drought stress compared to the number of root. The root of Xiang Potato 1 could not grow under 15% PEG stress and Zhongshu3，Dongnong303, Favorita, Jinshanshu were restricted by 25% PEG treatment. Interestingly, the roots of Atlantic potato, Zhongshu5 and S.chacoense1 could develop even under 30% PEG stress. Membrane permeability of seedlings increased with increasing concentration of PEG. The level of drought resistance varied among varieties of potatoes. The results revealed that the effect of PEG-induced water stress on seedling morphology was in accordance with the effect on membrane permeability.