Belonging to the field of biomedical materials, the invention relates to a preparation method of a polysaccharide-nanometer bacterial cellulose composite wound dressing. The method specifically consists of the steps of: taking a nanometer bacterial cellulose membrane for pretreatment and purification treatment so as to obtain purified nanometer bacterial cellulose, then preparing a polysaccharide solution with a concentration of 0.1-10%, removing part of water from the nanometer bacterial cellulose membrane, then compounding it with a polysaccharide solution by means of soaking, tape casting or spraying so as to obtain a polysaccharide-nanometer bacterial cellulose composite membrane, then conducting extrusion dewatering and ionizing radiation disinfection, thus obtaining the polysaccharide-nanometer bacterial cellulose composite wound dressing. The dressing of the invention has the advantages of good biocompatibility, cellular affinity and antibacterial property as well as mechanical property, excellent permeability, breathability or drainage, and moisture absorption effects, and has the efficacy of sterilization, inflammation diminishing, hemostasis, pain relieving, infection reduction and the like. At the same time, the dressing can promote wound surface drying, incrustation and healing, and can be used to treat burns or scalds, open wounds, ulcers, chronic wounds and stubborn infected wound surfaces, etc.