This study was carried out to determine the best mixing ratio of French dressing containing onion juice which was added at with different levels (12, 24, 36, and 48%). The mixing methods of ingredients were evaluated through sensory evaluation and viscosity and color of were measured. Instead of soy bean oil, we also studied various oils(corn oil, grape seed oil, canola oil, and olive oil) for the purpose of determining functional French dressing. The results were as follows; The results of the sensory evaluation showed that the French dressing with 36% added with 36% onion juice was the preferred most in appearance, flavor, and overall preference. Correlation coefficients between overall preference and sensory characteristics of onion added French dressing were higher in the order of taste (r=0.64), flavor (r=0.54), texture (r=0.48), appearance (r=0.41). The quality of French dressing varied greatly depending on the mixing methods of ingredients. The best method for making dressing was mixing 5 mL of oil with the other ingredients at 5 seconds intervals. The results of the sensory evaluation on French dressings with added onion juice containing soybean oil, corn oil, grape seed oil, canola oil, and olive oil, indicated that soybean oil was the most preferable. The appearance and taste of French dressing containing soybean oil were significantly the highest with regard to preference.