The invention relates to a low-caffeine instant tea powder with fragrance remained and a preparation method thereof. The preparation method comprises the following steps: step (1), tea polysaccharideseparation; step (2), caffeine separation; step (3), membrane concentration; and step (4), drying. The method combines four new technologies including caffeine solubility change, membrane separation,membrane concentration and vacuum freeze-drying, is efficient and energy-saving, and has no contact with organic toxic solvent. The method removes caffeine as well as well retains the original tea fragrance components. The method has low cost and short separation period. The method removes caffeine as well as well retains the original tea fragrance, so that the product is mellow in taste, bright in soup color and good in color, fragrance and taste. The product is green, safe and environmentally friendly, has a final removal rate of 99.5% or above, and has basically no pesticide residue. The product is the same as a tea raw material except that the product has no special caffeine flavor. The product is loose, porous, bright in color, in a crystal slice shape, and good in cold-solubility, and generates no scum at the time of brewing.