Abstract: In order to understand the changes in the content of cold-tolerant substances in jujube trees in different periods,the jujube branches of the first generation of Dongzao, the second generation of Dongzao, Ma Yazao and Ma Naizao were used as research materials, and the four cold tolerance indexes in January and February were measured. The results showed that the content of soluble protein and malondialdehyde in jujube trees in February was higher than that in January; the soluble sugar content was lower than that in January; There was a significant difference in the water content between the Ma Yazao and the second generation Dongzao. The water content in February was higher than that in January; there was no difference in the water content between the Ma Naizao and the first generation Dongzao. The change of the above substances indicates that the jujube tree has been relieved of natural dormancy in February and the metabolism is enhanced.

Key words: different periods, Dongzao, physiological index, dormancy