The invention belongs to the technical field of biological fermentation, and particularly relates to an active fermentation object, a preparation method of the active fermentation object, and application of the active fermentation object to cosmetics. The preparation method comprises the steps: S1 oat bran and water are taken to be mixed, then enzyme treatment is conducted, after enzyme treatment,sterilization is conducted, and an oat bran culture solution is prepared; S2 the oat bran culture solution is taken to be transferred into a fermentation tank, schizophyllum commune strains subjectedto three-stage culture are inoculated for fermentation, and a schizophyllum commune polysaccharide fermentation solution is obtained; and S3 the schizophyllum commune polysaccharide fermentation solution is taken to be filtered through a plate-and-frame filter press, a schizophyllum commune fermentation extracellular product is obtained, and then the schizophyllum commune fermentation extracellular product is micro-filtered and washed with water through a ceramic membrane till the clear and bright active fermentation object is obtained. The method is low in production cost, and simple and stable in process, and the obtained fermentation object containing active components such as oat beta-glucan and schizophyllum commune polysaccharide has the remarkable repairing and moisturizing effectson the skin, is high in stability, and has good application prospects in the field of the cosmetics.