The invention discloses a preparation method for hair-growing serum. The preparation method comprises following steps that (1) spices are soaked, specifically, 20g of red ginsengs, 40g of angelica sinensis, 40g of cacumen biotae, 45g of ligusticum wallichii, 20g of hemp fimble leaves, 25g of Chinese honeylocust fruits, 35g of dried radix rehmanniae, 50 of flos carthami, 30g of gynostemma pentaphyllum, 45g of phryma, 40g of polygonum multiflorum, 30g of mulberries, 40g of hemlock, 45g of chrysanthemum, 30g of fructus lycii, 20g of poria cocos and 25g of folium mori are soaked in a closed container with 1kg of ethyl alcohol and 2kg of water at the room temperature; and (2) residue filtering and liquor taking are conducted, specifically, herb residues are filtered out, liquor is taken, and the obtained liquor is a finished product. Compared with the prior art, the preparation method is simple in process, convenient to control, capable of saving time and effort and low in cost, and the prepared finished product is good in smell and quite prominent in effects of hair losing prevention, hair growing, hair breeding and hair nourishing.