Abstarct: Today, the use of salicylic acid as one of the plant hormones has increased in increasing the resistance of plants to stresses such as drought and light. Therefore, in order to investigate the phytochemical and morphophysiological responses of the medicinal plant (Thymus daenensis Celak) to salicylic acid foliar spraying under different conditions of drought stress and experimental light in the form of a factorial split plot and in the form of a randomized complete block design with three replications in the research field. Medicinal plants research institute located in Heljard Karaj village was conducted during two crop years 2016 and 2017. The investigated factors include water stress in three control levels or lack of water stress (usual irrigation until the end of the growth period), interruption of irrigation before flowering and interruption of irrigation after flowering as the main factor and the effects of two factors of light intensity including the control (absence of use of canopy net or shade), 50% light (use of canopy net or 50% shade) and salicylic acid foliar spraying in three control levels C1= (no acid use), C2= salicylic acid (0.1 mM) and C3= Salicylic acid (0.2 mM) were included as a sub-factor. The results of composite analysis of the data obtained from two years of experiment showed that the interaction effect of water and light stress and salicylic acid foliar spraying had a significant effect on all traits including leaf length, number of lateral branches, canopy diameter, number of reproductive stems, number of leaves on main reproductive stem, fresh and dry weight of aerial and reproductive organs, chlorophyll a, chlorophyll b, total chlorophyll, carotenoid, anthocyanin, electrolyte leakage, relative leaf water content, essential oil percentage, essential oil yield, soluble sugars, protein, proline, thymol, carvacrol and also enzymes Antioxidants include: catalase, glutathione peroxidase, ascorbate peroxidase and superoxide dismutase. 0.1mM salicylic acid foliar spray had a higher efficiency than the control in the stress level. The interaction of water and light stress had a significant effect on biological performance. Along with water stress and 50% reduction of light, its value was reduced to 16.27% compared to the control, although salicylic acid foliar spraying could not compensate for the negative effects caused by stress on biological performance. Application of salicylic acid (0.1 mM and 0.2 mM) increased the amount of beta-caryophyllin in Denai thyme plant under water stress by 52%. The amount of beta-caryophyllene increased with increasing light. In general, from the results of two years of experimentation, it can be concluded that salicylic acid, by inducing stress tolerance, moderated the damage caused by water and light stress in the Danai thyme plant, therefore, by improving the morphological, physiological and biochemical characteristics, it improves growth and increased essential oil Therefore, the use of 0.1 mM salicylic acid is suggested in the conditions of water and light stress in this plant.