Abstract: The present invention relates to the technical field of medical dressings, in particular to an antibacterial polyurethane sponge and a preparation method therefor. An antibacterial dressing, which is obtained by means of adding an antibacterial effective component to a molded polyurethane sponge dressing in a soaking or spraying mode, has a poor antibacterial durability. According to the present invention, on the basis of the problem, a water dispersion system of an antibacterial agent is pre-dispersed in a polyurethane prepolymer and then foamed, which enables the antibacterial agent to be encapsulated in the porous structure of a polyurethane sponge and achieves the effect of slowly releasing antibacterial metal ions, so that the prepared antibacterial polyurethane sponge has a good antibacterial durability.