The invention discloses a preparation process of corn edible oil, which comprises: 1, mixing corn germ powder and citric acid according to a certain weight part ratio, extracting, and evaporating to remove a solvent to obtain corn crude oil; 2, performing standing and precipitating the crude oil for 40-60 minutes, filtering by using a filter, and deodorizing; 3, roasting the whole corn grains at the constant temperature of 50-60 DEG C through a stirring tank, and putting the roasted corn grains into a squeezer to be squeezed to obtain oil; and 4, washing the white sesame seeds and the perilla seeds with warm water, drying in the air, mixing and stirring with all the raw materials, heating to 100-115 DEG C, reacting for 1-5 minutes, standing, and drying to 35-40 DEG C. The method has the beneficial effects that the corn germ powder and the whole corn grains are used for branch type crude oil squeezing, the content and the quality of the crude oil in the initial step can be improved, so that the process treatment delicacy is improved, and the required reaction conditions in the whole preparation process become milder.