The invention discloses a nursery stock growth regulator and a preparation method thereof. The nursery stock growth regulator is prepared from, by weight, 16-25 parts of zinc sulfate, 6-11 parts of naphthylacetic acid, 7-11 parts of chlormequat chloride, 3-5 parts of abscisic acid, 4-7 parts of potassium sulfate, 2-6 parts of brassinolide, 15-21 parts of plant straw, 7-12 parts of potassium butanoate, 6-12 parts of potassium sorbate, 1-4 parts of rooting agent and 3-8 parts of rooting powder. The effective formula of the zinc sulfate, the naphthylacetic acid, the chlormequat chloride, the abscisic acid, the potassium sulfate, the brassinolide, the plant straw, the potassium butanoate, the potassium sorbate, the rooting agent and the rooting powder is adopted, the problem of water shortage and drought of nursery stocks is solved, root system growth is promoted, the survival rate of transplanted nursery stocks is improved, the pore opening degree of the nursery stocks is effectively decreased, the transpiration is inhibited, the water content of leaves is increased, the free amino acid content is increased, the chlorophyll content is increased, and the survival rate and drought resistance of transplanted nursery stocks is greatly improved.