Background <p>Soil salinity poses a significant threat to global agricultural production. Wild barley (<i>H. spontaneum</i>), the ancestor of cultivated barley, offers valuable genetic diversity for stress adaptation. This study compared salt tolerance among six barley varieties (two wild barley, two salt-tolerant, and two salt-sensitive cultivated barley), by employing analysis of root/shoot growth and physiological traits under salt stress conditions.</p> Results <p>To explore the physiological basis of salt tolerance differences among six barley varieties, multiple indicators including photosynthetic capacity, ion homeostasis, stomatal regulation, and reactive oxygen species (ROS) scavenging ability were analyzed. Additionally, tissue damage was assessed using histological staining and fluorescence imaging techniques, and the accumulation differences of sodium ions (Na⁺), potassium ions (K⁺), and reactive oxygen species were visualized. Salt-tolerant cultivated barley maintained superior photosynthetic performance and root Na⁺/K⁺ homeostasis compared to salt-sensitive varieties, but no significant differences were observed in stomatal regulation and ROS scavenging ability. Wild barley performed better than cultivated barley in all measured parameters, exhibiting enhanced photosynthetic capacity, stomatal regulation, more stable ion homeostasis, and higher ROS scavenging ability.</p> Conclusion <p>By integrating multiple physiological indicators, this study clarified the differences in physiological characteristics among wild barley, salt-tolerant cultivated barley, and salt-sensitive cultivated barley. Additionally, we identified specific physiological limitations of current salt-tolerant cultivated varieties compared to wild barley. These findings provided reference for future breeding strategies to develop salt-tolerant barley.</p>