Salinity is a major constraint to crop productivity worldwide. Piriformospora indica was shown to promote the growth and also enhance resistance/tolerance to biotic and abiotic stresses. This work was intended to study the potential of P. indica in enhancing growth and elevating salt resistance in barley (Hordeum vulgare L.). Physiological and morphological experiments were used to investigate the metabolome changes in inoculated plants. The seedlings were inoculated with P. indica and 2 weeks after inoculation were treated with three salt stress levels. Four weeks after inoculation, leaf samples were collected and metabolite was extracted from leaves of inoculated and noninoculated barley (cultivar Pallas) plants. The physiological results showed that P. indica increases the biomass of aerial parts of inoculated plants compared with control plants under ambient and stress condition. Also, fungus affected ion content in inoculated plants and increased the K+/Na+ and Ca2+/Na+ ratios. The metabolomic results revealed that P. indica increases the sugars and free amino acid content in inoculated plants compared with control plant under salt stress. According to the results, this fungus can be used to produce growth-stimulating agents and biological fertilizers for use in crop production.