Soybean oil is the most consumed oil worldwide due to its cheapness but presented a weak thermo-resistance compared to most other oils used. This study aims to improve the thermo-stability of soybean oil by blending with crude oils. For this, physicochemical and antioxidant parameters of each blended oil were assessed before and after thermal treatment at 170°C for 10h/day for 5 days. The results of binary blended oils indicated that soybean oil mixed with lentisk, sesame, and almond oils (70:30%) manifested the best thermo-stability parameters. The Simplex Lattice Mixture Design applied for these three selected oils indicated that the combination of soybean oil at the proportion of 70% with lentisk oil and sesame oil at proportions of 17.7% and 12.3% respectively was selected as the best blending for maximizing soybean oil properties. Fatty acids analysis by GC/FID technique showed that the level of the degradation of linoleic acid (ω6) and linolenic acid (ω3) after heat treatment was more important in soybean oil than in blended oil. This study demonstrated that the thermo-resistance and nutritional quality of soybean oil were improved by blending with sesame and lentisk oils.