The invention mainly relates to the technical field of aquaculture, and discloses a feed additive for larvae of hypophthalmichthys molitrix. The feed additive is prepared from the following raw materials: fructus paulowniae, ulmus parvifolia leaf, toxicodendron succedaneum leaf, folium celtidis sinensis, fructus viticis negundo, caulis et folium lespedezae bicoloris, fructus caulis celastri, lonicera maackii, folium robiniae pseudoacaciae, viburnum dilatatum leaf extract, white granulated sugar, lactic acid bacteria and complex enzyme. The feed additive disclosed by the invention is rich in raw materials, is extracted from pure plants, contains no any toxic reagents, and is green and environmental-friendly; the raw materials are firstly steamed and boiled under high temperature and is then frozen under low temperature, so that the extraction of effective ingredients is quickened; the raw materials are fermented through the lactic acid bacteria, so that the palatability is increased, the food intake of the larvae of the hypophthalmichthys molitrix is increased, the disease resistance of the larvae is increased, and growth and development are promoted; the raw materials are respectively extracted through water, salt and an alcohol solution, so that the extraction rate is increased by 12.7 percent, and the production cost is reduced; the feed additive is convenient to use and small in dosage, the resistivity and the growing speed of the larvae of the hypophthalmichthys molitrix can be enhanced, the morbidity is reduced to 4 percent, the length of the larvae is up to 27.3mm when the larvae are 20 days old, and the survival rate is up to 98 percent.