Abstract: In order to explore the mitigation effect of salicylic acid（SA） on Atractylodes tyloseedlings under high temperature stress, and to select the optimal SA concentration suitable for alleviating high temperature stress injury. The effects of 3 different concentrations of SA solutions, including 0.5 mmol L^-1,1.0 mmol·L^-1 and 2.0 mmol·L^-1, and different degrees of high temperature treatment on the chlorophyll fluorescence parameters, root scanning parameters and root vitality of the leaves were studied. The result showed that, in terms of Fv′/Fm′、ΦPII and NPQ measured by chlorophyll fluorescence, the NPQ values of blank group were higher than those of treatment group under high temperature stress, while the Fv′/Fm′ and ΦPII values of blank group were lower than those of treatment group, and the SA solution sprayed with 0.5 mmol·L^-1 had the most significant effect compared with the control group. Spraying 0.5 mmol·L^-1SA could promote the root surface area of the seedlings under high temperature stress, and the promoting effect of spraying 1.0 mmol·L^-1SA was more significant in terms of root length, projected area and average diameter. The highest value of root activity was found in the seedlings sprayed with 1.0 mmol·L^-1 SA solution. In conclusion, the SA of 0.5 mmol·L^-1 can effectively alleviate the damage of high temperature on white surgery seedlings.