The invention provides a nut oat pastry and a preparation method thereof. The nut oat pastry comprises the following raw materials in parts by weight: 50-70 parts of high gluten flour, 50-70 parts of low gluten flour, 35-55 parts of whole wheat flour, 45-60 parts of oatmeal, 150-180 parts of butter, 120-170 parts of fine granulated sugar, 15-25 parts of egg yolks, 45-65 parts of broken nuts, 2-3 parts of salt, and 4-6 parts of baking soda; the nut oat pastry also comprises 5-10 parts of traditional Chinese medicine powder obtained through extraction on hawthorn, chrysanthemum, honeysuckle, radix salviae miltiorrhizae, rhizoma corydalis and malt, and 5-10 parts of coarse grain cereal powder obtained from coix seeds, semen phaseoli, buckwheat, peanuts and peas. In the formula of the product of the nut oat pastry obtained by the preparation method according to the present invention, the traditional Chinese medicine powder with health functions and the coarse grain cereal powder rich in dietary fiber are added, so that the product has not only rich nutrition, but also has certain effects of reducing blood lipid, blood glucose, and cholesterol and losing weight, and is crispy fragrant and sweet in taste; surface of the nut oat pastry is embedded with uneven broken nuts, and accompanied by irregular cracks, so as to greatly increase appetites when being seen; and the nut oat pastry is a good health-preserving snack product.