Abstract: Late spring coldness often cause great loss for Shanxi walnut industry. In order to guide production and provide scientific basis for walnut coldness breeding, the research took relative electric conductivity, SOD activity, POD activity, CAT activity, contents of soluble sugar and MDA on young leaves of Juglans nigra L .and 8 walnut cultivars were measured. Leaf cold resistance of different walnut cultivars would be evaluated by these indexes. Under low temperature, relative electric conductivity of Jinboxiang No.1 had small change and keep less than 0.5 under every treatment; MDA content of Juglans nigra L and Zhongling No.1 maintain a low level; soluble sugar content of Juglans nigra L, Zhonglin No.1 and Xiangling keep at a higher level under every treatments; Under low temperature stress Jinboxiang No.1 and Lipin No.1 had higher SOD activity, Liaohe No.1, Jinboxiang No.6 and Jinboxiang No.1 had higher POD activity, Lipin No.1and Zhonglin No.1 higher CAT activity. Indexes correlation analysis and indexes synthesis analysis of different cultivars also have been done. Combining field survey and indexes analysis, the comprehensive conclusion was leaf cold resistance of Liaohe No.1, Jinboxiang No.6, Black walnut, Lipin No.1 and Xiangling are strong. Principal component analysis could give a more comprehensive conclusion for multi-indexes estimation.