The invention belongs to the processing technology field of tea drinks and relates to a preparation method of Grateloupia sparsa tea. The preparation method comprises the following steps: grasping and washing fresh Grateloupia sparsa with fresh water, filtering, airing to remove fishy smell, and drying at a constant temperature for later use after cutting into small slices; selecting finished product Trikeraia hookeri, removing roots, and cutting into small slices for later use, roasting finished product sophora flower bud for later use, screening finished products, namely ginger peel and balsam pear pickle, respectively crushing into small slices for later use, grinding dry lotus seed for later use, after airing fresh honeysuckle, removing impurities, selecting and cutting into small slices for later use; manually separating a caterpillar body and a bacteria base for Cordyceps sinensis, and separately crushing for later use; weighing the Grateloupia sparsa, the Trikeraia hookeri, the sophora flower bud, the ginger peel, the balsam pear pickle, the lotus seed and the honeysuckle according to the weight proportion of formula, manually stirring and mixing, packaging in small bags according to the standard of each bag of 2-10g, finally adding Cordyceps sinensis powder, vacuumizing and sealing in bags. The preparation process is mature, scientific in formula, free from toxic and side effect and applicable for wide crowd.