Drought is one of the most important limiting factors in crop production. The use of seed treatment with optimal concentrations of plant growth hormones such as salicylic acid and application of useful microorganisms such as mycorrhizal fungi are the methods that can improve drought tolerance. The purpose of this study was investigating the effects of treatment with salicylic acid and inoculated with mycorrhizal fungi at different levels of irrigation in the flax plant. A factorial experiment base on randomized complete block design with 6 replications (3 replications for root characteristic study at flowering stage and other traits and 3 replications for measuring yield and yield compounds) was performed in growth chamber in 2010-2011. Treatments were irrigation regimes at 3 levels (100%, 70% and 40% field capacity), mycorrhizae at 3 levels (non-inoculated and inoculated with two species Glomus mosseae and G. intraradices ) and salicylic acid in 2 levels (seeds treated with 250 ?M concentration of salicylic acid for 8 hours and non-treated seeds). Seed emergence, plant height, leaf area and umber per plant, days to flowering (during vegetative growth), proline, relative water content, carotenoids, chlorophyll a, b ??and total chlorophyll, antioxidant enzyme activity, stem and leaf and total plant dry weight, root length , root dry weight, shoot phosphorus, soil phosphorus, hyphae and vesicle diameter, percent colonization, number and weight of capsules per plant, number of seeds per capsule and seed yield per plant were determined. The level of 40% field capacity irrigation reduced the leaf area and leaf number, relative water content, root length ,root dry weight, height, stem and leaf and total plant dry weight, number and weight of capsules per plant, number of seeds per capsule and seed yield and increased proline, enzymes activity of peroxidase and ascorbate peroxidase, soil phosphorus, days to flowering, vesicle diameter and percent colonization but had no effect on shoot phosphorus, carotenoids, chlorophyll a, b ??and total chlorophyll, hyphae diameter, enzymes activity of catalase and glutathione reductase. Both mycorrhizal species in the three levels of irrigation had increased some of the investigated traits and drought tolerance of flax plants inoculated with both mycorrhizal increased rather than non-inoculated plants. Under drought conditions, G. mosseae was the best species because increased in the number of capsules per plant and number of seeds per capsule in this study. Salicylic acid increased the percentage of seed emergence, height, enzymes activity of glutathione reductase and days to flowering but decreased carotenoid, enzymes activity of ascorbate peroxidase and peroxidase, leaf area and number, length and root dry weight, hyphae diameter, stem and leaf and total plant dry weight, moreover hadn’t any significant effect on other investigated characteristics. Interaction between the mycorrhizal and salicylic acid showed that inoculation with mycorrhizal and treatment with salicylic acid reduced the investigated characteristics than the inoculation with mycorrhizal and non-application of salicylic acid. This indicated that there was no synergistic effect between mycorrhizal and salicylic acid. The results showed that the 100% field capacity and Glomus mosseae species ware the best irrigation level and mycorrhizal fungi respectively. Key words : Glomus mosseae , G. intraradices , salicylic acid, drought, antioxidant enzymes, flax