The invention discloses a green vegetable flour and a preparation method thereof, and is characterized in that the green vegetable flour is prepared from the following raw materials in parts by weight: 500-530 parts of wheat, 10-12 parts of wheat germs, 4-5 parts of propolis, 20-22 parts of chrysanthemum coronarium, 30-35 parts of sweet potato leaves, 20-25 parts of coriander, 20-22 parts of water chestnut, 18-20 parts of taro, 7-8 parts of fermented soyabeans, 5-6 parts of an ovary and digestive glands of a crab, 5-6 parts of milk candy, 8-9 parts of a konjac powder, 2-3 parts of grapefruit peel, 1-2 parts of semen pruni, 1.5-2.5 parts of cynomorium songaricum, 2.5-3 parts of platycladi seed, 1-1.2 parts of fructus aurantii immaturus, 0.9-1.2 parts of radix polygonati officinalis, 1-1.2 parts of viola arcuata, 0.8-1 parts of saussurea nigrescens, and 10-11 parts of a nutrition additive. The flour is fine and smooth in mouthfeel; due to the addition of the chrysanthemum coronarium, sweet potato leaves and other vegetables, the taste is faint scent, the color and luster are bright green and beautiful, and contained crude fibers are beneficial for helping intestinal tract motion; and with collocation of the added semen pruni and various Chinese herbal medicines, the flour can reach the efficacy of clearing hollow viscera and relieving bowel.