Soil salinity, one of the most widespread environmental stresses in arid and semi-arid regions, has inhibitory effects on plant establishment and performance. In order to investigate the effect of combined application of growth-promoting bacteria and biosolids on physiological indices of psyllium, an experiment was conducted as a factorial in a randomized complete block design with three replications in field conditions. The experimental factors included PGPR at four levels of control, Bacillus halotolerans, Bacillus amyloliquefaciens and a mixture of both bacteria, irrigation water salinity at four levels of 0.3 as control, 4, 8 and 12 dS/m and three levels of biosolids at 0, 10 and 30 ton/ha. The results showed that salinity stress reduced nutrients potassium, magnesium, calcium, soluble sugars and chlorophyll a and b by 33%, 3%, 35%, 19%, 43% and 61%. In contrast, it increased the levels of antioxidants, total phenols and proline by 156%, 89% and 152%, respectively. The combined application of biosolids and PGPR, especially at high salinity levels, led to an improvement in magnesium content by 68%. Also, bacterial inoculation reduced sodium concentration by 29% in the plant. The use of bacteria significantly increased soluble sugars by 69% and proline by 130% and reduced antioxidant content by 14% and 8% phenols. In general, the combination of B. halotolerans and B. amyloliquefaciens bacteria plays an effective role in improving the physiological indices of the medicinal plant under saline conditions. These findings emphasize the need to combine modern microbiological solutions with intelligent management of organic resources in saline land improvement programs. This approach, by creating a sustainable synergistic cycle between organic matter and beneficial soil microorganisms, improves soil fertility and physical properties, leading to significant increases in the sustainability, resilience, and productivity of agricultural systems under environmental stress in arid and semi-arid regions