Abstarct: Nowadays, the application of antioxidants and plant growth regulators has bean discussed for decreasing the negative effect of different stresses. Ascorbic acid and Sodium nitroprosside have bean substance caused witch the resistance to biotic and abiotic stresses. To evaluate the effect of ascorbic acid and sodium nitroprosside foliar application on some traits of safflower (Carthamus tinctorius), a field experiment design was carried out in split plot factorial baxsed on randomized complete block in shahrood university. Two levels of irrigation, including 8 days interval (well watered) and 16 days interval (water deficit stress) were in main plot, and foliar of sodium nitroprosside in 3 levels (0, 50 and 100 µM) and Ascorbic acid in 3 levels (0, 10 and 20 mM) were in sub plots. Stress treatment applied after plants establishment completely. The first foliar application of sodium niroprosside and ascorbic acid was performed in 63 and 65 days after sowing respectively. and then repeated after 1 week. Results showed that water stress decreased the fertile capitol weight, total dry matter, sub sub branch, capitol diameter, kernel weight and number of seeds in capitol. The stress increased relative water content (RWC) and membrane Electerical Conductivity (EC). The number of infertile capitol per plant, number of hallow seeds per plant and seed coat kernel ratio increased by drought stress. Ascorbic acid foliar application increased fertile capitol weight, capitol diameter and number capitol per plant. The number of infertile capitol, number of hallow seeds per plant, RWC and EC decreased by ascorbic acid foliar application. Ascorbic acid in 20 mM concentration increased significantly 0.69% in seed protein compared with control. The fertile capitol weight, total dry matter, capitol diameter, 1000 seeds weight and EC increased significantly by sodium nitroprosside foliar application. Seed protein increased 1% by application 100 µM concentration. Seed yield by application 100 µM sodium nitroprosside concentration was 13.2% more than control. Sodium nitroprosside foliar application decreased the infertile capitol per plant and seed coat to kernel ratio. The result showed that the application 100 µM sodium nitroprosside concentration and 20 mM ascorbic acid concentration contained highest fertile capitol weight and increased 35.1% compared with control. 10 mM ascorbic acid foliar application 100 µM sodium nitroprosside concentration decreased the hallow seed weight. Consequently, in this experiment, 20 mM ascorbic acid and 100 µM sodium nitroprosside concentration can be introduced as the best treatment compound.