The invention provides a cotton straw-enhanced plastic-wood product which comprises the following components: 30-50 parts of short fiber wood materials, 10-30 parts of cotton straw long fibers, 25-45 parts of waste recycled plastics, 1-4 parts of lubricants, 0.2-1 parts of stabilizers, 1-2 parts of coupling agents, and 1-5 parts of other additives, wherein the other additives comprises one or more than one of an ultraviolet absorber, an antioxidant, a flame retardant, a colorant, and a compatilizer. The preparation method of the cotton straw-enhanced plastic-wood product comprises the following steps of: short fiber wood material treatment, cotton straw long fiber preparation and treatment, material mixing, granulation, and extrusion molding. The method enhances the mechanical properties of the plastic-wood product by reasonably preparing the cotton straw long fibers, and adding the cotton straw long fibers into the plastic-wood product. The plastic-wood product of the invention is green and environment-friendly, has no limitation of shape, and has wide applications and low cost.