This study identifies a potentially new salt-tolerant bacterium, Oceanobacillus sp., temporarily named OC2, selected from wetlands. In the absence of plant companions, OC2 does not reduce soil salinity; however, in coexistence with plants, it triggers unique mechanisms that lower soil salinity by approximately 12.4% and enhance plant salt tolerance, indicating a special interaction between OC2 and plants. Our investigation reveals that OC2 produces IAA and attracts plant roots to grow toward it, facilitating its entry into the roots. Under salt stress, OC2 secretes metabolites that stimulate the plant to synthesize proline, increasing levels by up to 98.5%, which enhances root osmotic pressure, while also increasing carotenoids and flavonoids in leaves to boost the plant's antioxidant capacity. In terms of the plant, the chemical substances secreted under salt stress trigger OC2 to produce more IAA (about 17%), stimulating root development for better water absorption. The presence of OC2 also enhances amylase activity in roots by up to 88%, breaking down starch to produce soluble sugars for OC2's use, suggesting a symbiotic relationship between the two. This study highlights the interactions between the newly discovered salt-tolerant bacterium and plants, with the potential to improve saline-affected agricultural land and increase crop yields.