Maize （Zea mays L.） is one of the most important crops for both human consumption and livestock feed， but its growth and yield are seriously constrained by salt stress. Therefore， developing salt-tolerant maize varieties is crucial for sustainable agriculture. In this study， we characterized the salt tolerance phenotypes and physiological responses in csp2-overexpressing transgenic lines （csp2^OE） within the CAL genetic background at the seedling stage. Compared to CAL， the csp2^OE lines exhibited significantly higher survival rates， reduced malondialdehyde （MDA） and hydrogen peroxide （H₂O₂） levels， enhanced catalase （CAT） activity and proline content. Additionally， the csp2OE lines showed lower Na⁺ content and Na⁺/K⁺ ratio in shoots， confirming that csp2 overexpression enhances salt stress tolerance. To further investigate the possible molecular mechanism of the csp2 gene under salt stress， the transcriptome sequencing was performed on CAL and the csp2^OE-72 line under both control conditions and 12 h of salt stress treatment. Differentially expressed genes （DEGs） were primarily enriched in the cell periphery， metabolic pathways， and plant hormone signal transduction， particularly the abscisic acid （ABA） response， starch and sucrose metabolism， and amino acid transmembrane transport. These findings demonstrate the significant role of csp2 in maize salt tolerance and suggest its potential for genetic improvement of salt-tolerant maize varieties.