Salt stress is a critical factor that affects the growth and development of plants. Salicylic acid (SA) is an important signal molecule that mitigates the negative effects of salt stress on plants. To elucidate salt tolerance in large pink L. (Caryophyllaceae) and the regulatory mechanism of exogenous SA on under different salt stresses, we conducted a pot experiment to evaluate leaf biomass, leaf anatomy, soluble protein and sugar content, and the relative expression of salt-induced genes in under 0.3, 0.6, and 0.9% NaCl conditions with and without 0.5 mM SA. The result showed that exposure of to salt stress lead to a decrease in leaf growth, soluble protein and sugar content, and mesophyll thickness, together with an increase in the expression of and genes. Foliar application of SA effectively increased leaf biomass, soluble protein and sugar content, and upregulated the expression of and in the , which facilitated in the acclimation of to moderate salt stress. However, when the plants were grown under severe salt stress (0.9% NaCl), no significant difference in plant physiological responses and relevant gene expression between plants with and without SA was observed. The findings of this study suggest that exogenous SA can effectively counteract the adverse effects of moderate salt stress on growth and development.