The effects of different concentrations of salicylic acid（SA） on the growth and physiological characteristics of oat under 0.5%NaCl stress were investigated by spraying with NaCl solution and SA. The results showed that:under 0.5% salt stress, the growth index of oat seedlings decreased significantly, and the plant height, root length,fresh weight, and dry weight ratio of oat after external SA were all increased, of which 1 mmol/L concentration was the best. In addition, the SOD, POD, CAT enzymatic activity and chlorophyll content in plants under NaCl stress decreased significantly, while the MDA content increased significantly. After 1 mmol/L SA was applied, MDA content decreased the most and chlorophyll content increased significantly. The activity of SOD, POD and CAT increased significantly. It can be seen that 1 mmol/L SA is the best for relieving 0.5%NaCl stress of oat.