The invention relates to the field of agriculture and forestry, and provides a seed dressing agent for promoting germination of plant seeds and a preparation method thereof. The seed dressing agent isprepared from the following raw materials in percentage by weight: 1 to 2 percent of silkworm chrysalis, 2 to 3 percent of starfish, 4 to 5 percent of cornu bubali, 3 to 4 percent of rhizoma imperatae, 2 to 3 percent of malt flour, 2 to 3 percent of kelp, 1 to 2 percent of leaves of pericarpium zanthoxyli, 2.5 to 3.5 percent of folium artemisiae argyi, 3 to 4 percent of orange peel, 2 to 3 percent of coriander, 3 to 4 percent of ficus carica leaves, 3 to 4 percent of reed root, 2 to 3 percent of alginic acid, 2 to 2.5 percent of imidacloprid wettable powder of which the concentration is 70 percent, 8 to 11 percent of amino acid, 0.8 to 0.9 percent of zinc sulfate, 3 to 6 percent of monopotassium phosphate, 0.5 to 0.8 percent of potassium sorbate and the balance of magnetized industrial water. According to the seed dressing agent disclosed by the invention, most raw materials required for production are natural materials, the environment is not polluted during a using process, the damage to the human body is avoided, the root system of the plant subjected to seed dressing by the seed dressing agent is developed, the stooling is strong and the activity of the root of the system is improved, the disease resistance of plants is enhanced, the drought resistance, the freezing resistance, waterlogging tolerance and the saline-alkaline tolerance of the plants are enhanced, the germination speed of the plant seeds is fast, seedlings grow strongly, an application range is wide, and the seed dressing agent is suitable for being used for seed dressing of multiple plants.