Abstract: Our research group is aiming to genetically engineer tall fescue to improve its salt tolerance, so that it can be used as a salt-tolerant turf grass to improve the soil in salt-contaminated environments. To this end, a regeneration system was established for tall fescue. Using embryogenic calli as the experimental materials, three salt tolerance-related AtSOS pathway genes from Arabidopsis thaliana (AtSOS1, AtSOS2, AtSOS3) were introduced in different combinations into the genome of the tall fescue cultivar‘Arid3’ by Agrobacterium-mediated transformation. The transgenic plants showed increased salt tolerance. Genomic DNA was extracted from the transgenic tall fescue plants, and PCR detection, Southern blotting, and RT-PCR analyses were conducted. The tall fescue plants transformed with different AtSOS gene combinations and wild-type plants were subjected to salt treatment, with three replicates for each line. The physiological and biochemical indexes, plant height, and Na⁺, K⁺, and chlorophyll contents were determined. Under salt stress, the superoxide dismutase (SOD), peroxidase (POD), hydrogen peroxidase (CAT) activities were significantly higher in the transgenic plants than in the control plants, and the malondialdehyde (MDA) and proline (Pro) contents were lower than those in the control plants. In the NaCl treatment, the Na⁺ and K⁺ contents in leaves were increased in transgenic and in wild-type plants. Most of the transgenic plants and wild-type plants showed reduced plant height and chlorophyll content under salt treatment, however, the chlorophyll content of transgenic plants harboring AtSOS1-AtSOS2-AtSOS3 was higher than that in control plants. These results demonstrate that the introduction of AtSOS pathway genes into tall fescue can increase its Na⁺ content under salt stress, alleviate the symptoms of salt stress, and improve its salt tolerance.