The invention relates to an oligosaccharide-containing soilless culture liquid fertilizer. The weight percentage of the oligosaccharide in the liquid fertilizer accounts for 0.2-4%, the weight percentage of the inorganic fertilizer accounts for 50-90%, the weight percentage of the antiseptic bactericidal substance accounts for 0-30%, the weight percentage of the algae removal substance accounts for 0-1%, and the balance of water, wherein the oligosaccharide can be selected from chitosan oligosaccharide, sodium alginate oligosaccharide, pectin oligosaccharide, isomalto-oligosaccharide, xylo-oligosaccharide and soybean oligosaccharide, and the inorganic fertilizer can be selected from more than two of the elements including nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, boron, iron, manganese, copper, zinc and molybdenum. Due to the reasonable proportion of the oligosaccharides, inorganic fertilizer, antiseptic bactericidal substance and algae removal substance, the oligosaccharide-containing soilless culture liquid fertilizer can improve the quality of the crops in all aspects.