Abstract: Effects of low temperature on the physiology and cold stress resistance of potato plants were studied for breeding and cultivation of winter-planting varieties in Guangxi. The physiological and biochemical characteristics of the leaves on 3 selected cultivars in response to low-temperature stress during seedling stage were monitored. Favorita, Xingjia No. 2, and Lishu No. 6 were selected for the study, and the contents of chlorophyll, moisture, soluble protein, and malondialdehyde (MDA), as well as the activities of superoxidedismutase (SOD), catalase (CAT), and peroxidase (POD) in the 5^th leaf on a plant were determined after the plant was grown at 4℃ for 0, 3, 6, 12, 24 or 48 h. The results showed that, the leaf relative water and chlorophyll contents of the 3 varieties declined continuously under the stress; and, at 48 h, those of Favorita became significantly lower than those of Xingjia No. 2 or Lishu No. 6. The soluble protein content and the activities of SOD and CAT in the leaves of the 3 varieties decreased initially but increased afterward. In contrast, POD activity rose at first and followed with a downward trend. Under the stress for 48 h, the soluble protein content and activities of SOD and POD in the leaves of Xingjia No. 2 and Lishu No. 6 were significantly higher than those of Favorita, while MDA increased constantly during this period. MDA in Favorita was significantly higher than the other varieties. The cold resistance of the cultivars ranked in the order of Lishu No. 6, Xingjia No.2, and Favorita. Compared to Favorita, which is the major potato variety cultivated in Guangxi, Lishu No. 6 and Xingjia No. 2 appeared to be more suitable for winter-planting to extended the growing season in the region.