The invention discloses a seedling-stage nutritional addition material stable in fertilizer efficiency and long in action period. The seedling-stage nutritional addition material is prepared from, by weight, 23 to 27 parts of coal slime, 22 to 24 parts of rice chaff ash, 1 to 2 parts of nitrilotriacetic acid, 10 to 14 parts of sodium nitrate, 16 to 18 parts of sawdust, 17 to 19 parts of chicken feather, 6 to 8 parts of fulvic acid calcium, 36 to 40 parts of volcanic rock, 18 to 20 parts of threonine mother liquor, 21 to 25 parts of aged tea, 72 to 78 parts of waste crop straw, 4 to 5 parts of composite fungal hyphae, and an appropriate amount of water. According to a preparation method, the seedling-stage nutritional addition material is prepared from common raw materials such as coal slime and waste chicken feather via a plurality of steps such as fermentation, chelation, and pelletizing, and is capable of improving soil physicochemical properties and nutritional characteristics; a large amount of fungus is added, so that the seedling-stage nutritional addition material is capable of providing seedlings with required nutrients, relatively stable complementary nutritional system among the bacteria is formed; dominant bacterial communities are formed; and activity of the seedling-stage nutritional addition material can be maintained for a relatively long time, and fertilizer efficiency is achieved.