The invention relates to the technical field of conditioning and nourishing formulas, in particular to a conditioning and nourishing formula for preventing cardiovascular and cerebrovascular diseases and diabetes mellitus and a preparation method thereof. According to the technical scheme, the formula comprises cereals, edible and medicinal dual-purpose nuts and Chinese herbal medicine nutrients, wherein the cereals comprise oat, hulless oat, buckwheat, black sesame, peanuts, purple perilla and black beans; the edible and medicinal dual-purpose nuts comprise walnut kernels, hazelnut kernels, Chinese chestnut pulp, pine nut kernels, hawthorn fruit pulp, figs, pistachio nuts, red dates, Chinese yams, burdocks and Chinese wolfberry fruits; the Chinese herbal medicine nutrients comprise semen boitae, polygala tenuifolia, poria cocos, gastrodia elata, radix rehmanniae preparata, American ginseng and rhizoma polygonati. The formula has the beneficial effects that the formula is beneficial to early prevention of cardiovascular and cerebrovascular diseases and diabetes mellitus, is suitable for a wide range of people, can balance nutrient substances in a human body, can comprehensively supplement important nutrient substances lacking in the human body, and has no adverse side effect.