Sesuvium portulacastrum has the remarkable ability to substitute Na for K in its growing leaves, enabling osmotic functions without adverse effects. When subjected to high salt stress, the plant absorbs Na + through its roots and transports it to the leaf parenchyma cells, where it is compartmentalized and stored in vacuoles. Additionally, salt ions crystallize to preserve cell turgor. S. portulacastrum adapts to high salinity environments by accumulating substantial amounts of glycine betaine, which helps maintain the normal synthetic metabolic processes of its cells. Several plants that overexpress the BADH gene exhibit significant improvements in salt tolerance. The 3D structure of the SpBADH reveals that VTLELGGKSP and Cys are crucial for its catalytic activity, while Tyr-163, Trp-170, Trp-288, and Trp-459 contribute to structural stability. Tyr-163 and Trp-459 are also involved in substrate recognition and specific binding. Overexpression of SpBADH in yeast AXT3K and Escherichia coli enhances salt tolerance. Further research has shown that overexpressing SpBADH in Arabidopsis leads to increased GB accumulation, which promotes Na + efflux, enhances K + recruitment, and thereby reduces Na + toxicity to the roots. GB also protects chloroplast structure, boosts the activity of ROS scavenging enzymes, alleviates photoinhibition of PS I and PS II, and improves Arabidopsis’ adaptation to salt environments by regulating ion balance. Intriguingly, we have found that GB plays a regulatory role akin to plant hormones, regulating cell damage repair and growth and development in Arabidopsis. Consequently, introducing the GB biosynthesis pathway into plants or applying exogenous GB could be an effective strategy to enhance plant salt tolerance.