The invention relates to a soilless culture substrate which is mainly applicable to seedling breeding of paddy rice and also applicable to seedling breeding of plants like flowers, grass and vegetables. The soilless culture substrate is characterized by containing any one selected from the group consisting of crushed rice hulls, furfural residues and xylitol residues, any one selected from the group consisting of brown coal powder, silicon calcium magnesium fertilizer and mushroom residues, dried cow dung, bentonite and insecticide-fertilizer. According to the invention, the soilless culture substrate contains a variety of micronutrient elements needed in growth of plants in a seedling stage and bactericides, has the characteristics of richness in nutrients, disease prevention, cold resistance, seedling strengthening, low cost, greenness, ecological environmental protection, convenient usage and the like, can create a good growing environment for the plants in a seedling stage, has good water retention performance, allows good consistency between a cover layer and a bottom layer to be obtained, can be directly used for bed paving, sowing, covering, thorough watering and mulching so as to breed standard seedlings, enables a high breeding rate of standard seedlings to be achieved, is beneficial for protection of ecological environment of farmlands and can realize recycling of agricultural wastes and standardized seedling breeding of plants; a preparation method for the substrate is scientific and reasonable, can be easily mastered and is convenient to operate.