The invention discloses a wet-rub resistant styrene-acrylic emulsion and the preparation method. The existing styrene-acrylic emulsion still can not reach the requirements under the conditions with high wet-rub resistance. The invention is takes styrene, butyl acrylate, methyl methacrylate and acrylic acid as the polymeric monomer of the system, the functional monomers containing ureido as the modified monomer of the system, compound emulsifiers as the emulsifier of the system, and thermal decomposition initiators as the initiator of the system, so as to prepare and obtain the wet-rub resistant styrene-acrylic emulsion through core-shell polymerization. The invention adopts the core-shell polymerization technology to enable the functional monomer components to be mainly distributed in the shell layers by controlling the dropping rate, so as to achieve the purpose of modifying the styrene-acrylic emulsion. The styrene-acrylic emulsion obtained through such a method has better wet-rub resistant performance and can be used as the base material of interior and exterior wall coatings, which has good prospects for development.