Sunflower oil (Antioxidant free) was treated with black seed and lettuce oil preparations at concentration of  0.1,0.3 and 0.5% , to study the improving stability of sunflower oil toward oxidation and  rancidity at  ambient , and thermal process at 120 ̊C for 18 hours. Radical scavenging activity DPPH% results indicated increased the ability of  scavenging activity for black seed oil preparation compared to lettuce oil preparation 95.62 and  88.02 %  and total phenolic compound contents ranged from 649.79 and 356.73mg/g  gallic acid respectively . While results of  HPLC indicated ellagic , benzoic and e-vanillic were higher in black seed oil preparation compared with  e-vanillic , benzoic and  catechol in lettuce oil preparation respectively. Obtained  data proved that acid , peroxide and  thiobarbituric  acid (TBA) values that sunflower oil treated with black seed oil were higher than the other treated with lettuce oil preparation  after thermal  process.  Black seed oil preparation caused the highest oxidative stability (highest induction  period)  7 and  6 hours  before and  after thermal process . The results indicated that the  0.5%  black seed oil preparation before and after thermal process and 0.5% and 0.1%  from lettuce oil preparation  regestied  the more  efficiency  before and after thermal process respectively.