The invention relates to a leisure food, namely a cereal nutrient biscuit and a preparation method thereof, belonging to the technical filed of food processing, which is composed of flour, white sugar, edible vegetable oil, black sesame seed, broken peanut, black soy milk powder, yam flour, rice powder, millet powder, corn powder, sorghum powder, oatmeal, fresh hen eggs, salt, sodium bicarbonate, ammonium bicarbonate and citric acid. The preparation method is as follows: evenly mixing the raw materials and stirring into paste; rolling the paste into the shape of biscuit and then baking; spraying palm oil on the surface of biscuits; cooling at room temperature; detecting the biscuits by a metal detector, removing biscuits containing metal chips or metal particles; picking out damaged biscuits; and packaging and warehousing the biscuits. In the invention, multiple grains such as sesame, peanuts and black beans are added to ensure more reasonable nutrition, no fumet is added to let the biscuits keep natural fragrance of rice; and the biscuit has the advantages of rich nutrition, multiple disease prevention, beautifying and body building, prolonging life, thin and crisp mouth feeling and the like, thus is a convenient leisure food suitable for people at all ages.