The invention provides a functional antibacterial composite wool flocculus. The functional antibacterial composite wool flocculus is mainly prepared from wool composite fiber webs, hot melting powder and silver nanoparticles, wherein the mass of the hot melting powder accounts for 7%-13% of the total mass of the wool composite fiber webs. The functional antibacterial composite wool flocculus has the advantages of being breathable, high in moisture removal property and capable of promoting sleep, enhancing the vitality, promoting cell metabolism, delaying ageing and inhibiting pathogenic bacteria and can effectively prevent many skin lesions and pruritus. The invention further provides a preparation method of the functional antibacterial composite wool flocculus. The method is simple, easy to operate and suitable for large-scale automated production.