The invention discloses a method for preparing flammulina velutipes sporocarp polysaccharides. The method comprises the following steps: extracting flammulina velutipes sporocarp with ethanol, and extracting with hot water to obtain a crude polysaccharide extracted solution; adding ammonium sulfate and an organic solvent, performing oscillation reaction, and centrifuging after oscillation reaction; dialyzing and drying a lower-layer water phase obtained by centrifuging to obtain the flammulina velutipes polysaccharides. According to the method, the flammulina velutipes polysaccharides are rapidly, conveniently and effectively extracted, the extraction rate and the purity of the flammulina velutipes polysaccharides are improved at the same time, and the antioxidant activity of the flammulina velutipes polysaccharides prepared through the method is remarkably superior to that of the flammulina velutipes polysaccharides prepared through a purification step.