The invention relates to a formula and preparation method of longan dry walnut kernel health care tea. According to the formula, the longan dry walnut kernel health care tea comprises 30-80g of longan, 10-50g of walnut kernel, 3-9g of American ginseng, 5-15g of liquorice and 500g of water. The preparation method of the health care tea comprises the following steps of: (1) cleaning; (2) material preparing: weighing 30-80kg of dried longan, 10-50kg of walnut kernel, 3-9kg of American ginseng and 5-15kg of liquorice and adding 500kg of water; (3) gelatinizing; (4) grinding into thick liquid; (5)filtering; (6) magnetizing: magnetizing and filtering mixed stock solution three times by virtue of a magnetizing filter, wherein the surface magnetism of a magnetic rod is 7000-11000Gs, the working temperature is 100 DEG C, and filtering accuracy is 50-2Mum; (7) blending; (8) homogenizing; (9) filling; and (10) sterilizing: carrying out high temperature sterilization on filled beverage, wherein the temperature is 121 DEG C and time is 25-45min. The invention has the beneficial effects that the longan dry walnut kernel health care tea prepared according to the formula has the effects of tonifying heart and kidney, nourishing the blood and tranquilization and stabilizing blood pressure; and after the longan dried walnut kernel plant beverage is magnetized, macromolecular group is changed into micro molecular group, the osmotic force, dissolving power and diffusive force of the longan dried walnut kernel mixed liquor are enhanced, and the health care effect is enhanced.