The invention discloses crab flavor mayonnaise and a preparation method thereof, and the crab flavor mayonnaise is characterized by being prepared from the following raw materials by weight: 2-3 parts of dodder, 3-4 parts of ganoderma lucidum, 4-5 parts of sweet scented osmanthus, 2-3 parts of lophatherum gracile, 4-4.5 parts of momordica grosvenori flower, 1.8-2 parts of machilus leptophylla hand.-mazz., 1-2 parts of polypodium hymenodes kunze, 3-3.5 parts of donkey hide gelatin, 60-65 parts of egg yolk, 4-5 parts of apple, 3-4 parts of asparagus lettuce, 3-4 parts of toona sinensis leaf, 4-5 parts of brown rice, 3-4 parts of red kojic rice, 4-5 parts of water chestnut, 4-5 parts of cashew nut, 7-8 parts of sweetened bean paste, 80-90 parts of rapeseed oil, 50-55 parts of crab meat, 6-7 parts of pomegranate wine, 3-4 parts of rice vinegar, 50-55 parts of milk and 6-8 parts of a nutritional additive. The crab flavor mayonnaise has good taste, is rich in milk fragrance, tastes sweet, is reasonable and scientific in formula, and can tonify the body by combination of nutrition of a variety of seafood, grains and nuts; in addition, the crab flavor mayonnaise is also added with a variety of Chinese herbal medicines, can reach the effects of tonifying kidney, nourishing liver, tonifying spleen, benefiting stomach, nourishing blood, activating blood, and lowering lipid by regular consumption, and is a kind of green healthy food.