Abstract: Taking ‘Early Maturity Excellence’ as the experimental material, four treatments were set up, room temperature spray of distilled water（HckW）,high temperature spray of distilled water（HW）,room temperature spray of 1 mmol · L^-1 spermidine（HckS）,and high temperature spray of 1 mmol · L^-1 spermidine（HS）.The regulatory mechanism of spermidine on jujube tree′s resistance to high temperature stress was studied, in order to provide reference for high-quality cultivation of jujube trees.The results showed that the growth rate of jujube trees under high temperature stress was significantly lower than that under normal temperature control and spermidine spray treatment.The photosynthetic pigment content of jujube trees treated with high temperature was significantly decreased, while SOD,POD,CAT activities and MDA,soluble protein, soluble sugar, Pro contents were significantly increased.The endogenous ABA content of jujube leaves sprayed with Spd at high temperature first increased and then decreased.The contents of endogenous Put, Spm and Spd increased obviously, and basically reached the highest value after one week of treatment and then began to decline.The response of jujube trees to high temperature stress was alleviated by spermidine spray.