Abstarct: Today medicinal plants, according to a special place in their community and health, scientific and research centers are considered. In this context and with a view to expanding the demand for treatment plants, it is necessary to investigate and develop research in this area are needed. Use of common purslane (Portulaca oleracea L.) as a food and medical plant has a long history. This plant is introduced as a treatment of all diseases in world health organization (WHO). Drought is the most important limiting factor for crop production and increasingly has become a major problem in many parts of the world. Water deficit is environmental stress that has negative and destructive effects on plant growth levels, structure and function. Nowadays, application of salicylic acid as a plant hormone in enhancement of plant resistance to stresses such as drought stress has increased.Predicted experiment for this research was carried out in factorial design baxse on random complete block design with three replications. Factors were salicylic acid sprayed with four levels (0, 0.5, 1, 1.5mM) and drought stress with three levels [no stress, mild stress and severe stress (6, 12, 18 days irrigation interval)]. Plants were sprayed before anthesis. The result of this experiment showed that effect of low irrigation had significant effect in 1% probability level on all characteristics. When the water deficit was become more, most of characteristics decreased except rate of prolin in leaf that had increased with more drought stress. Expectedly chlorophyll b in severe stress then mild stress increased. Salicylic acid sprayed acid had no effect on leaf and seed oil content. The levels of salicylic acid, application of 1mM salicylic acid increased plant height, the number of capsule, the number of seeds in capsule, carotenoids and rate of prolin. Plants which treated with 1mM salicylic acid under control condition had highest number of seed in capsule, chlorophyll a and carotenoids. But plants with 0mM salicylic acid treatment and without drought stress had highest 1000 grain weight. Finally, the use of salicylic acid under drought stress condition improved plant characteristics quantity and quality.