The invention discloses edible oil and a preparation process thereof. The edible oil is prepared from, by weight, 50-60 parts of peanut oil, 30-40 parts of soybean oil, 16-20 parts of camellia-seed oil, 11-15 parts of walnut oil, 10-12 parts of grape seed oil, 8-10 parts of Argan oil, 6-8 parts of cannabis oil, 5-7 parts of rice bran oil, 10-14 parts of mutton fat and 0.1-0.3 part of grease improver; the grease improver is prepared from, by weight, 23-49% of glucose oxidase, 20-30% of phosphatidyl ethanolamine, 9-15% of nano-selenium, 2-3% of vitamin E, 1-2% of tea polyphenol, 5-7% of lycopene, 4-6% of carnosol, 2-4% of chlorogenic acid and 8-10% of phytic acid. The preparation process of the edible oil comprises the steps of preparation of the grease improver, preparation of compound grease and preparation of the edible oil. The edible oil and the preparation process thereof have the advantages that by moderately increasing the proportion of saturated fatty acid in the edible oil, thefatty acid structure is improved, the grease improver is utilized to prevent the occurrence of browning reaction, the content of dissolved oxygen is reduced, and the heat stability and inoxidizability of the edible oil are improved.