The invention provides a preparation method of a tailorable and washable silk floss flocculus, which comprises the following steps that 1), three raw fiber materials, namely a silk fiber, a polyester three-dimensional crimp hollow fiber and an ES (Ethylene-Propylene Side By Side) fiber are weighed according to mass percent, opened, and mixed uniformly, wherein the silk fiber is 55-80%, the polyester three-dimensional crimp hollow fiber is 10-35%, and the ES fiber is 5-20%; 2), the mixed raw fiber materials are subjected to carding and web forming, and a fiber web is subjected to disorder drafting; 3), the fiber web is fed into a needling machine for needling reinforcement; 4), the fiber web is fed into a hot air drying room for hot air bonding solidification; and 5), the flocculus is slit, subjected to ultraviolet sterilization and packed. The silk floss flocculus prepared by the method reserves the advantages of lightness, softness, comfortability, health care, heat preservation, breathability and the like of a silk product, and introduces the advantages of the polyester three-dimensional crimp hollow fiber, so that the heat preservation performance and the bulkiness are improved, and the production cost is lowered appropriately.